ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 415 



foot. For a geological period so remote as the Trias, the high degree of 

 specialisation in this diminutive Dinosaur is truly astonishing. 



Colour-pattern in Tortoises.* — J. E. Duerden shows how in the 

 South African genus Homopus a gradation in complexity of colour- 

 pattern can be traced through the five known species, the simple con- 

 centric pattern of the shields being broken up into a spotted or rayed 

 pattern. The more highly-differentiated patterns in the allied genus 

 Testudo can all be interpreted through the stages found in Homopus. 

 In some species the ontogeny of the colour-pattern repeats its inferred 

 phylogeny. The diverse colour-patterns seem to stand in no direct 

 causal relation with environmental conditions. 



Viviparity in Proteus anguineus.f — J. Nusbaum describes an 

 interesting case. A female Proteus, which had taken no food for 

 \?> months, gave birth to a young animal, 12 '6 cm. in length, ex- 

 tremely transparent, with two well-developed eyes, with certain defects 

 in its extremities, but on the whole fully formed. It is probable that 

 it nourished itself at the expense of eggs which had been passed into 

 the oviduct, and that the uinisual mode of birth was due to the artificial 

 conditions of captivity. 



Swim-bladder of the Flat Fishes.J — Otto Thilo discusses the 

 subject of the disappearance of the swim-bladder in flat fishes. He 

 indicates in the first inst<ince a number of structural facts, skeletal and 

 otherwise, which point to a relationship between them and Zeus, rather 

 than with the Gadidje. Thus Boulenger's group Zeorhombi is justified. 

 Various young flat fishes, e.g., Rhombus, Solea, Arnoglossus laterna, 

 are known to have a swim-bladder, which later is lost. This loss the 

 author traces to the change of habit from a pelagic to a bottom one. 

 The presence of the bladder would render it diiflcult for the fish to 

 remain on the sea-floor. Its actual disappearance is brought about by 

 mechanical pressures of various kinds due to differential growth as well 

 as to external conditions. 



Frontal Gibbosity in Ptychochromis.§ — J. Pellegrin discusses this 

 frontal prominence which occurs in various fishes, particularly in the 

 pharyngognathous Acanthopterygii. He describes it in two species of 

 Ptychochromis. It consists of a prominence made up of connective- 

 tissue laden with fat surmounting the occipital crest, and spreading out 

 to the right and left. Its development appears to be- related to that of 

 the testes in males ; it probably consists of reserves for the development 

 of the sex-glands. 



Fishes of Australia.|| — David G. Stead has done a useful piece of 

 work in giving a popular and systematic guide to the study of Australian 

 fishes. He does not attempt to deal with the thousand or so species of 

 fishes from Australian waters, but confines himself to the more im- 



* Records of the Albany Museum, ii. (1907) pp. 65-92 (12 figs.). 



t Biol. Centralbl., xxvii. (1907) pp. 370-5 (1 fig.). 



t Zool. Anzeig., xxxi. (1907) pp. 393-406 (7 figs.). 



§ Comptes Rendus, cxliv. (1907) pp. 1168-70. 



i! Fishes of Australia, Sydney, 1906, 278 pp. (10 pis. and 88 figs.). 



