TWO NEW SPECIES OF ON YOHOPHOKA. 489 



and an apical part which may be either conical, cylindrical, 

 or spherical in form, ami carries on its top a pointed spine; 

 the latter consisting merely of a conical elevation of the skin. 

 The basal portion of the primary papillae almost invariably 

 stretches across the folds of the skin from one groove to the 

 other, while that of the accessory papillae only occupies a 

 portion of that area. The scales which cover the basal por- 

 tion of the primary papillfe, and correspond to the epidermal 

 cells of the skin, are shorter and broader than those which 

 cover the apical part. 



In the species Weldoni all the papillae have a somewhat 

 polygonal and distinct basal outline, and the consecutive folds 

 of the skin come so close together as almost to obliterate 

 the grooves between them (fig. 10); while in the species 

 Horsti the papillte have a round and indistinct basal outline, 

 and the grooves between the folds are at least half as wide 

 as the folds themselves (fig. 13). In Weldoni it is not 

 unusual to find secondary papillae situated in the grooves; 

 while in Horsti they scarcely ever occupy that position; in 

 the former the grooves are narrow and shallow, and the folds 

 rise up gradually ; in the latter the grooves are broad and 

 deep, and the folds rise up suddenly. 



The Median External Openings: — Inthefemale there 

 are only three median openings, while in the male there are 

 four. The latter has an opening which does not occur in the 

 female, and which is situated between the last pair of leo-s. 

 It was described by Horst as the anus, which he said was 

 sub terminal (8). 



The Mouth: — The mouth is surrounded by a ring of 

 yellowish-white papillse of large size. Inside the ring, and 

 in front of the actual mouth-opening, are situated four pairs 

 of large papilla, which become smaller in size from in front 

 backwards. Between these internal papillae the so-called 

 tongue appears, and carries a number of complex denticles 

 (fig. 4 and fig. 14). 



The Anus: — The anus is a small, longitudinal slit-like 

 opening, situated at the terminal end of the animal. In 



VOL. 44, PART 4. NKW SERIES, 1 1 



