摘要:

The relationship between crossvein defects and wing length was investigated in lines ofDrosophilaunder disruptive selection on the IV longitudinal vein to get a better knowledge of the mechanism by which this selection determines divergence.

ISSN:0373-4137    

DOI:10.1080/11250007809440103

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

In the crested newt the effect of synthetic TRH was tested “in vitro” on cultures of thyroid associated with pituitary glands. The results seem to confirm also in the Urodele Amphibians the activating effect of TRH; the action of this hormone — like that of TSH used under the same conditions — is suggested by the more rapid release of131I metabolized by the thyroid.

ISSN:0373-4137    

DOI:10.1080/11250007809440104

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The role of fatbodies in the normal gonadal function of the male frogRana hexadactylahas been studied. Present experiments have revealed that the hypothalamus exercises a control through hypophysis over the mobilization of fatbody contests which in turn control the testicular activity. The metabolites of the fatbody contents are released into the testis through the direct blood supply between the two organs which has been established by earlier workers. The role of A, and B2cells of the pars distalis in the mobilization of fatbody contents has already been reported. It has been found in the present study that gonadrotrophins could not stimulate gonads in the absence of fatbodies. In view of these observations, a possible modus operandi has been discussed.

ISSN:0373-4137    

DOI:10.1080/11250007809440105

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A study of the qualitative and quantitative composition of the macrozobenthos of the Bacchiglione River, from Padova to the sea, enabled us to get general conclusions about the quality of its waters.

ISSN:0373-4137    

DOI:10.1080/11250007809440106

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Electrophoretic method has been applied to biochemical classification of Mugilids in the Lagoons of the Po delta. Among the various proteins analysed the one which turned out to be the most useful was the lactate dehydrogenase enzyme (LDH) because it presents different patterns in the five species living in the above mentioned lagoon and does not show any variations in the course of ontogenesis. This caracteristic makes it possible to identify stocks of fry to be put into closed waters for subsequent cultivation. Moreover this method allows one to make certain phylogenetic speculations with regard to the origin of these species.

ISSN:0373-4137    

DOI:10.1080/11250007809440107

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The relationship between the results obtained under two shuttlebox conditions, one with a brief electrical shock as unconditioned stimuls (US) (classical type) and another with a mechanical shock as US (adapted type) are illustrated. The differences in acquisition of the responses suggest the usefulness of the shuttlebox with the application of mechanical shock for the study of conditioning in marine Teleost fishes.

ISSN:0373-4137    

DOI:10.1080/11250007809440108

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The male mesonephric terminal segments ofHydromantes italicusandTriturus italicushave been studied.

ISSN:0373-4137    

DOI:10.1080/11250007809440109

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The parameters characterizing the processes of birth, growth, death, reproduction and production ofDaphnia longispinain Lake Santo Parmense, a mountain lake in Northern Apennines (Italy), have been estimated for the period lasting from June to the beginning of September 1973: in this period the population is mainly constituted by parthenogenetic females and presents the highest seasonal values of density and biomass. The production ofD. longispinahas been calculated using the compartmental model proposed by De Bernardi and Di Cola (1976) for the study of the biomass dynamics in populations with continuous recruitment.

ISSN:0373-4137    

DOI:10.1080/11250007809440110

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A house mouse population, homozygous for 8 pairs of Robertsonian metacentrics (2n = 24) has been discovered in the Po Valley area between the Ticino and the Adda. In the lower reaches of Ticino and along the Po specimens can be found which display hybrid chromosome sets between the Robertsonianly transformed karyotype and the Standard Mouse karyotype. East of the Adda river a house mouse population has been discovered with the 22-chromosome karyotype previously described for the Orobian and Valtellina populations. The relations of this new Robertsonian population with the other members of the Rhaetian system (Orobian, Poschiavo, Mesolecina and Engadine) are discussed.

ISSN:0373-4137    

DOI:10.1080/11250007809440111

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The spontaneous motor activity in the trout embryo was investigated by electrophysiological methods. Two aspects were examined: the temporal and the developmental pattern. As for the temporal pattern, with the present investigation it was possible to demonstrate the presence of cycles whose length varied from 5 to 17 min. depending on the stage examined.

ISSN:0373-4137    

DOI:10.1080/11250007809440112

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor