266 



A. E. SHfPLEY 





rior lialf ol' this swelling is bare, just as is the posterior half of 

 E. turbinella (fîg. 5). Whether the retinaculum is a fixed point or 

 not I am not quite sure ; if it be, this différence would be important . 

 but if the swelling of the body which forms the retinaculum be 

 capable of shifting slightly, now taking in part of the neck and 

 now ineluding part of the bare space (fîg, 4) which lies between the 



retinaculum and the proboseis and 

 which is retracted and invisible when 

 the proboscis-sheath is withdrawn, 

 then the disposition of the scales is 

 easily explained. 



Borgstrôm's ligures of young spéci- 

 mens of E. porrigens are a little smaller 

 but bear a considérable resemblanee 

 to von Linstow's figures of E. capi- 

 tatus. 



Although 1 was inclined at one time 

 to place this species, i.e. E. capitatus, 

 as a synonym of E. porrigens, I now 

 think that the présence of hooks on 

 the retinaculum in E. capitatus and 

 their absence in E. porrigens is a dis- 

 tinction of spécifie value. 



There can I think be little doubt 

 that E. porrigens Rud. is a separate 

 species. The two spécimens I received 

 from Professor Gollett are some 18 e " 1 

 in length with a few wrinkles in their 

 otherwisé smooth body. Borgstrôm's 

 spécimens wei-e smaller, a large one 

 with him being but 11"" long. The visible portion of the proboseis 

 is short, but this m a y be due to its rétraction info its sheath. 

 The retinaculum, — that swollen pat't of the body which follows 

 the proboseis ancl which serves to keep the parasite in position in 

 the pit or cavity which ils présence bas hollowed out in the niucous 

 membrane of the hosl's intestine — is very broad and shallovv 

 From side to side in my spécimens it measured 6 mm but it is so 

 flattened from behind forwards as to be almost disk like. A fealure 



Fig.5. — Echinorhynchus capila 

 lus von Linstow. — A, natura 

 size ; B, head of the samo entai- 

 ged, after Parona. 



