The chromosomes of two species of the genusOryzomys (rodentia-cricetidae)

Resumen Oryzomys es un género altamente politípico y primitivo que ocupa un área geográfica que se extiende por todo el continente Sudamericano y el sur de Norteamérica. De este género se describen los cromosomas de dos especies pertenecientes al subgéneroOryzomys. O. albigularis (posiblementeO. a. camcolus) (2N=66) yO. delicatus (2N=60) cuyos cromosomas son fundamentalmente del tipo acrocéntrico o subtelocéntrico con algunos pares matacéntricos o submetacéntricos.     

The karyotype ofMicrotus cabrerae Thomas,another species with giant sex chromosomes

Summary The karyotype ofMicrotus cabrerae, a species endemic to Spain, is described. It comprises 2n=54 chromosomes, with a fundamental number of 64, and with very large sex chromosomes. An evolutionary relationship between this species andM. chrotorrhinus is suggested.     

Karyological heterogeneity in the Falconiformes (Aves).

Chromosome studies in 4 families of Falconiformes, Cathartidae, Falconidae, Sagittariidae and Accipitridae showed that the karyological variety in this order is much wider than in any other avian order, which underlines the heterogeneous character of the group. Of the 4 families only the Cathartidae show karyological similarities with other avian groups (Gruiformes, Ciconiiformes), while the karyotypes of the Accipitridae are most uncommon among birds, because of the presence of only 8 microchromosomes.     

Germ cell chromosomes in two species of terrestrial isopods from India

Summary In 2 species of terrestrial isopods, namelyPorcellio assamensis andP. laevis, the diploid and haploid numbers of chromosomes have been established to be 48 and 24 respectively for the former species and 50 and 25 respectively for the latter species. Female heterogamety of the ZW type has been found to exist inP. laevis.The authors express their sincere thanks to Prof. G.P. Sharma, and to Prof. S. Khera, Department of Zoology, Panjab University, Chandigarh, for the necessary laboratory facilities.     

The somatic chromosomes of 3 lizard species:Gekko gecko,Iguana iguana,andCrotaphytus collaris

Zusammenfassung Die somatischen Chromosomen der 3 EidechsenartenGekko gecko (2N=38),Iguana iguana (2N=34) undCrotophytus collaris (2N=36), werden dargestellt.G. gecko besitzt metazentrische, subteleozentrische und teleozentrische Elemente, aber keine Mikrochromosomen.I. iguana undC. collaris besitzen Makrochromosomen (6 Paare) und Mikrochromosomen. Bei den ArtenG. gecko undI. iguana waren in keinen von beiden Geschlechtern heteromorphische Chromosomenpaare nach zuweisen.

---

---

Supported by Project No. 417 from the U.S. Children's Bureau and Grant No. 08737 from the National Cancer Institute.     

The chromosomes ofBufo rubropunctatus andBufo chilensis (Anura,Bufonidae) and other species of thespinolosus group

Summary The chromosomes ofBufo rubropunctatus andB. chilensis (on basis of adults) are described for the first time. These chromosomic sets are compared with the karyotypes ofB. spinolosus andB. variegatus and other species ofspinolosus group. The importance of the secondary constrictions applied to the phylogeny ofBufo are discussed.Supported by Proyecto N⁰ S-77-47, Dirección de Investigación, Universidad Austral de Chile.I would like to thank Dr J. M. Cei for collecting the Argentinian toads. Mr N. Diaz collected the specimens from Santiago, Chile.The technical assistence of Sonia Lacrampe is acknowledged with appreciation.     

Comparative study by scanning electron microscopy of synovial surfaces of four mammalian species

Zusammenfassung Die Oberflächen der Gelenke von Mensch, Kaninchen, Schwein und Ratte zeigen elektronenmikroskopisch feine zottenartige Bildungen. Daneben finden sich auch leichte Vertiefungen. Diese Bildungen sind für eine gleichmässige Gelenkbewegung von Wichtigkeit.     

Karyomorphology of two species ofTor (Pisces; Cyprinidae) with a high number of chromosomes

Summary The karyotypes ofTor khudree andTor tor, occurring in the Himalayan streams in India, are described. As reported earlier forT. putitora, the diploid complements in these 2 congeneric species also comprise 100 chromosomes. The modal number being 2n=50 in this family,Tor appears to be of tetraploid origin.The author is greatly indebted to Prof. G.K. Manna, and Prof. A.K. Bose, Department of Zoology, University of Kalyani, for encouragements and laboratory facilities. Financial aid from the University of Kalyani is gratefully acknowledged. Sincere thanks are also due to Dr M.K. Jyoti and Miss Anu Agarwal of the Department of Biosciences, Jammu University for their cordiality and help in various ways during my stay at Jammu.     

The chromosomes of the didelphiid marsupialMarmosa robinsoni bangs

Résumé L'étude des chromosomes somatiques du marsupial sudaméricainMarmosa robinsoni Bangs, démontre que l'équipement chromosomique diploïde de cette espèce de la subfamille Didelphiinae est composé de 14 chromosomes. Trois paires d'autosomes sont grands et submétacentriques; 1 paire est formée par de chromosomes moyens, métacentriques, et 2 paires sont acrocentriques et plus petites. Le complexe sexuel est du typeXY, formé par unX métacentrique et unY télocentrique, tous les 2 étant les chromosomes les plus petits du complément. La similitude de ce caryotype avec celui du genreCaluromys, appartenant à la subfamille Microbiotherinae, est remarquable.     

Electrical response of bat retina to spectral stimulation: comparison of four microchiropteran species

Summary Electrical responses of the retinas of 4 species of microchiropteran bats stimulated by spectrally restricted light flashes were found to diverge systematically from the rhodopsin absorption spectrum. The divergence was progressively greater across the 4 species. The results appeared explainable by assuming a second photoreceptor class and photopigment which was present in progressively greater numbers in the retinas ofEptesicus fuscus, Desmodus rotundus, Artibeus jamaicensis andCarollia perspicillata.This work was made possible by equipment provided by grant No. EY 01228 from the U.S.P.H.S., Bob Hope Fight for Sight award No. G 522 and a grant from Research to Prevent Blindness, Inc. Portions of this work were presented at the Fifth International Bat Research Conference, Albuquerque, New Mexico, August 11, 1978.The authors would like to express appreciation to Drs A.M. Potts, J. B. Longley, R. S. Crockett and T. G. Wheeler for helpful suggestions and to Drs J. H. Richardson, J. G. Cooper, L. Kundrotas, Mr B. Spoonamore and Mr W. Lopez-Forment for facilitating collection and importation of the Mexican bats.     

Male sex-comb teeth number in four species of theDrosophila bipectinata complex and their hybrids

Summary The number of teeth in the sex-combs of males of theDrosophila bipectinata complex differentiates species. In addition, the character distinguishes a majority of hybrids. A polygenic model of inheritance is proposed.     

Effect of light adaptation on electrical responses of the retinas of four species of bats

Summary The levels of light adaptation at which the retinas of 4 species of microchiropteran bats became unable to generate electroretinograms were progressively ordered. The order correlated well with light preferences based on activity patterns of the 4 species. These results suggest that the ability of the retina to function in ambient light may govern some natural behaviors of these bats.This work was supported in part by grant No. EY 01228 from the U.S.P.H.S. and was facilitated by equipment provided by Bob Hope Fight for Sight Award No. G522 and a grant from Research to Prevent Blindness, Inc. Portions of this work were presented at the Fifth International Bat Research Conference, Albuquerque, New Mexico, USA, August, 1978.     

Electrical response of bat retina to spectral stimulation: comparison of four microhiropteran species.

Electrical responses of the retinas of 4 species of microchiropteran bats stimulated by spectrally restricted light flashes were found to diverge systematically from the rhodopsin absorption spectrum. The divergence was progressively greater across the 4 species. The results appeared explainable by assuming a second photoreceptor class and photopigment which was present in progressively greater numbers in the retinas of Eptesicus fuscus, Desmodus rotundus, Artibeus jamaicensis and Carollia perspicillata.     

Effect of light adaptation on electrical responses of the retinas of four species of bats.

The levels of light adaptation at which the retinas of 4 species of microchiropteran bats became unable to generate electroretinograms were progressively ordered. The order correlated well with light preferences based on activity patterns of the 4 species. These results suggest that the ability of the retina to function in ambient light may govern some natural behaviors of these bats.     

Flavonoids from pollens and stigmas of male and female flowers of four species of the genusCucurbita

Summary Differences have been found between the flavonoid patterns of pollens and corresponding stigmas ofCucurbita pepo, C. maxima, C. moschata andC. ficifolia. The major flavonoids ahve been identified as isorhamnetin-3-O-rutinoside isolated from stigmas ofC. pepo is absent in this material.Acknowledgments. The author thanks Dr Chr. Karl (Weleda, Schwäbisch Gmünd) for a sample of isorhamnetin and Mr A. D'Urso (Botanic Institute, University of Catania) for help in acquiring the plant material.     

Chromosomes in four species of rodents of the genusCtenomys (Rodentia,Octodontidae) from Argentina

Résumé Les chromosomes de 4 espèces de rongeurs fouisseurs du genreCtenomys de la Province de Tucumán, Argentine, ont été étudiés dans des cellules somatiques de la moelle osseuse. Le nombre diploïde est de 22 chromosomes dansC. occultus, de 28 dansC. tucumanus et de 42 dansC. latro. Un seul individu mâle deC. tucunax a présenté un complément de 2N=61.     

The chromosomes ofCalamoichthys calabaricus (Pisces,Polypteriformes)

Riassunto È stato descritto il cariotipo di un Polypteriforme,Calamoichthys calabaricus, Smith. Il numero diploide, 2n=26, le dimensioni dei cromosomi e la stessa morfologia del cariotipo mettono in evidenza le affinità filetiche intercorrenti tra Polypteriformi e Dipnoi e la linea evolutiva tetrapoda, diversificandoli, al contrario, dagli altri primitivi Attinopterigi, Holostei e Chondrostei.