ANATOMY AND DEVELOPMENT OP PERIPATUS OAPENSIS. 247 



muscles and tracheae, and when cut away from its attachment 

 the muscles and tracheae cannot easily be detached from it- 

 The main part of the coils are formed by region No. 1, and 

 the epithelial cells lining this part present very characteristically 

 the striated appearance which has already been spoken of. The 

 large-celled region of the coiled tube (fig. 27) is also of con- 

 siderable dimensions, and the terminal portion is wedged in 

 between this and the commencing part of the coiled tube. 

 The terminal portion with its internal opening is in its histo- 

 logical characters exactly similar to the homologous region in 

 the hinder nephridia. 



The three pairs of nephridia in the three foremost pairs of 

 legs are very rudimentary, consisting, so far as I have been 

 able to make out, solely of the collecting vesicle and the duct 

 leading from them to the exterior. The external opening is 

 placed on the ventral side of the base of the feet, in the same 

 situation as that of the posterior nephridia, but the histological 

 characters of the vesicle are similar to those of the fourth and 

 fifth pairs. 



Generative Organs. 



[The sexes are distinct, and the average size of the females 

 appears to be greater than that of the males. 



The only outward characteristic by which the males can be 

 distinguished from the females is the presence in the former of 

 a small white papilla on the ventral side of the 17th pair 

 of legs (PI. II, fig. 4). At the extremity of this papilla the 

 modified crural gland of the last leg opens by a slit-like 

 aperture. 



The generative orifice in both sexes is placed on the ventral 

 surface of the body, close to the anus, and between the two 

 anal papillae, which are much more marked in small specimens 

 than in large ones, and in two cases (of females) were observed 

 to bear rudimentary claws. 



1. The Male Organs. PI. XX, fig. 43. 



The male organs consist of a pair of testes {te), a pair of 



