112 



single dorsal fin, lias appeared to the same naturalist to require 

 generic distinction, and he has accordingly described it as the type 

 of a new genus, to which he has given the name of Platysome: it is 

 evidently, from the brief notice contained in the < Analyse,' the 

 Dules caudavittatus, Cuv. and Val., or a nearly allied species, a fish 

 which certainly differs considerably, by its compressed form and 

 other particulars, from many of those with which it was generically 

 associated by the authors last quoted. M.J. Lienard has exhibited a 

 drawing of an Acanthurns: and M. J. Desjardins has described three 

 fishes of the genera Serranus, Labras, and Xirichthys; and has 

 also exhibited and described specimens, obtained from the north- 

 western coast of Sumatra, of eight other fishes. 



Among the Crustacea, two species of Crabs common on the coasts 

 of the Mauritius, and belonging to the genera Poriunus and Pod- 

 ophthalmus, have been described and drawn by M.J. Lienard. 



Finally, M. E. Lienard has described minutely a marine sub- 

 stance which he has regarded as an Alcyonium : he proposes to con- 

 tinue to figure and describe the numerous zoophytes which abound 

 in the adjoining seas to such an extent as to render the Mauritius 

 highly favourable for the pursuit of zoological studies in this beau- 

 tiful but intricate department of nature. 



Mr. Gray exhibited living specimens of the common Lizard, La- 

 certa agilis, Linn., for the purpose of pointing out the marks of dis- 

 tinction between the sexes. The male is generally larger than the 

 female, and more distinctly coloured : the under side of his body and 

 base of his tail are very bright orange, while in the female these parts 

 are pale yellowish green -, his ante-anal scale is short and transverse, 

 that of the female being much longer and hexagonal ; and the under 

 side of the base of his tail is flat, with a slight longitudinal middle 

 depression just behind the vent, this part of the tail being in the fe- 

 male rounded and convex. In April and May the male may also be 

 known by the base of the tail being dilated on the sides, just behind 

 the thigh, a dilatation probably caused by the size of the penes, which 

 are retracted into these parts. 



Mr. Gray further explained various particulars of the habits of this 

 species, observed by him in individuals which he had kept in a living 

 state ; and added, that in the only instance in which he had observed 

 the coitus, one alone of the penes was inserted. 



