296 Zoological Society : — 



The skull is more flattened than in other species, and remarkable 



for a strongly developed ante-orbital crista. 



metre. 



Total length 0089 



Length of the head 0-021 



of the ear in front 0-014 



Breadth of the ear 0012 



Length of humerus 0024 



of forearm , 0*037 



of thumb 0O085 



of second finger 0-0335 



of third finger 0'067 



of fourth finger 0*0505 



of fifth finger 0-035 



of thigh 0-013 



of tibia 0-0105 



of foot with claws 0-008 



of tail 0-019 



of free end of the tail 011 



2. Mus, sp. ? 



A very young, indeterminable specimen, with only two molars de- 

 veloped. Above brown, penicillated with black, with the bases of the 

 hairs blackish grey ; below white. In its colour and the length of 

 the ear, this species is allied to the South-African Fieldmice, as Mus 

 colonus, M. natalensis, &c. 



The Reptiles, which Dr. Giinther has named for me, consist of 

 two Snakes (Dijisas colubrina and Herpetodrxjas Bernieri), a Cha- 

 meleon (Chamceleon lateralis, Gray), several fine specimens of a 

 Lizard of the genus Gerrhosaurus (G. lineatus, Cocteau = Ciciyna 

 ornafa, Gray), and an example of another Lizard (Liolepisma Belli, 

 Gray). All these are species already known to the fauna of Mada- 

 gascar. 



The Crayfish I have submitted to Mr. Spence Bate, as our lead- 

 ing authority on this branch of natural history. Mr. Spence Bate 

 pronounces it to be a new species of Astacus, which he proposes to 

 call after its discoverer, with the following characters : — 



Astacus Caldwelli, Spence Bate, sp. nov. 



The eyes are planted on short peduncles. The first pair of an- 

 tennae have the third joint of the peduncle reaching to the extremity 

 of the rostrum. Both branches of the flagellum are slender; and 

 the primary branch, which is half as long again as the secondary, 

 is about half the length of the anterior division of the cephalon. 

 The second pair of antennae are about three times the length of the 

 first. ; and the flagellum is minutely articulate, each articulus being, 

 in length, less than half its breadth, and at the basal extremity being 

 about half the breadth of the last joint of the peduncle. The s<jua- 



