ZOOLOGY AND BOTANY, MICROSCOPY, KTC. 429 



the skin, did not immediately affect the ordinary discharges. After an 

 hour the intensity of discharge was slightly modified, and by the end of 

 five or six hours it was reduced by one half. There was never complete 

 suppression even up to the end of eight days, and on being returned to 

 the water recovery took place. 



Geographical Variation in Pleuronectids.* — M. A. Cligny has 

 made some observations on the dorsal and anal fin rays, and finds that 

 the variations which exist do not depend on either age or sex, but that 

 there is a progressive multiplication of rays ; the forms with fewest 

 occur furthest north, and these are more primitive. 



Comparative Description of Lepadogaster bimaculatus Pennant 

 and microcephalus Brook, f — F. Guitel has given a very exhaustive 

 description of these two species, comparing the two sexes in each, and 

 devoting a chapter to sexual differences. These two species which 

 formerly were confounded, are easily separated in the male sex ; the 

 females are very similar, and in the young state are like the male of 

 microcephalus. In L. bimaculatus the interesting discovery has been 

 made that forms inhabiting the laminarian zone have in their kidney no 

 tubuli contorti, while those dredged from deeper water possessed those 

 tubules in varying degrees. 



Reproductive Organs of Amphioxus.J — B. Zarnik gives an account 

 of the development of the gonad in both sexes, a statement of its struc- 

 tural relations, and also some histological details. He describes an ex- 

 cretory function which he finds is possessed by both ovary and testis, 

 and in discussing their morphological significance claims Amphioxus as 

 a very valuable connecting link between segmental invertebrates and 

 vertebrates. He claims that the gonads arise from the mesoderm which 

 in Selachii produce the primitive kidney ; they are themselves excretory ; 

 their blood supply may be homologised with that of the Selachian 

 primitive kidney ; and there are other points all of which support the 

 view that the gonads of Amphioxus are homologous with this organ. 



Phylogeny of Post-caval Vein.§ — W. Woodland describes a specimen 

 of Rana temporaria in which the post-caval vein was absent, and replaced 

 by a persistent right posterior cardinal. This abnormality has led him 

 to seek a phylogenetic explanation of the origin of the post-caval vein. 

 He finds it is related to the development of limbs which are locomotor 

 (Tetrapoda) rather than balancing. So long as the trunk and the tail 

 constitute one continuous locomotor body, so long is there little chance 

 of the two posterior cardinals approaching the median line and com- 

 pletely fusing at a point midway in the length of the trunk, since this 

 point is necessarily anterior as regards the body as a whole, and ante- 

 riorly flexion is of small degree. With locomotor limbs flexion of the 

 trunk becomes accentuated, and acquires a new distribution. The primi- 

 tive posterior cardinals are subject to a new distribution of forces, and, 



* Comptes Rendus, cxl. (1905) pp. 526-9. 



t Arch. Zool. Exp., ser. 4, ii. (1904) pp. 357-495 (1 pi.). 



X Zool. Jahrb., xxi. (1904) pp. 253-338 (5 pla.). 



§ Zool. Anzeig., xxviii. (1905) pp. 737-47. 



