STRUCTURE OF THE VERTEBRATE SPERMATOZOON. 487 



together of less capacity than the first vacuole. These 

 slowly increased in size, and after a time fused together to 

 form one large vacuole, precisely like that from which they 

 were derived. 



Lithamoeha discus is thus seen to be a uninucleate form 

 with contractile vacuole. In the vacuolar differentiation 

 of its protoplasm, its concretions, and hernia-like pseudo- 

 podia, it presents affinity with the multinucleate Pelomyxa, 

 which has crystalline bodies in place of concretions, and no 

 contractile vacuole. 



In the structure of its nucleus and delicate cuticle 

 Lithamoeha is unlike any other form, whilst the combination 

 of characters which it presents entitles it to a very distinct 

 position amongst the Amoeboid Gymnomyxa. 



The concretions appear to be, very probably, only a larger 

 form of the refringent granules which are present in great 

 quantity in the protoplasm of the common large Amoebse. 



On the Structure of the Vertebrate Spermatozoon. 

 By Heneage Gibbes, M.B. (With Plate XXIV.) 



In making an examination into the structure of the 

 spermatozoa of Vertebrate animals those of the Amphibia, 

 such as the Triton cristatus and Salamandra maculata, from 

 their large size, afford the best examples. Taking then the 

 living spermatozoon of either of these animals in the fresh 

 condition just removed from the body we find the following- 

 appearances, shown in figs, 1 and 2, of Salamandra maculata, 

 and fig. 3, of Triton cristatus. 



Fig. 1 was drawn from a specimen of Salamandra 

 maculata, mounted in a \ per cent, solution of sodium 

 chlorate. 



Fig. 2, also in the same solution, under a lower power. 



Fig. 3, spermatozoon of Triton cristatus, had been placed 

 in a solution of chromate of ammonium and then mounted 

 in glycerin . 



From these illustrations it will be seen that the spermato- 

 zoon consists of (a) a long -pointed head, at the base of which 

 is {])) an elliptical structure joining the head to (c) a long 

 filiform hody ; [d) a fine jilament^ much longer than the 

 body, is connected with this latter by (e) a homogeneous 

 membrane. 



