TFir: (lEPirviiEA of japax. 81 



ASPIDOSIPHOX 



I. Skin-papilla3 distinct. A single fixing muscle and a rectal gland 

 ]iresent. 



A. — Both anal and caudal shields present. 



(I. — The two shields radially grooved. 



I-. — Longitudinal nniscle separated into very irre- 

 gular bundles. Retractor muscles arise from the 

 inside of the caudal shield.... J. truncatuf<. P. .38. 

 2. — Longitudinal muscle separated into more or less 

 regular bundles. Retractor muscles arise far an- 

 terior to the caudal shield.... J. sfeenstrup/i. 1\ 40. 

 />. — The peripheral border of the anal shield only is 

 lightly grooved. 



Longitudinal muscle continuous. Retractor 

 muscles arise just in front of the caudal shield. 



A. ')iti.'^al-/rnms. F. 41. 



B. — Caudal shield indistinct. 



The anal shield is of the shape of a tall, ob- 

 liquely directed cone ; it is very thick and 

 calcareous, and its siuface roughened by the 

 presence of distinct radial ridges and grooves.,,. 



A. nm'i^r/itdfns. P. 43. 



II. No papillîo over the greater part of the body pro])f-r. No fixing 

 muscle or rectal gland. 



ff. — The two shields show a jirominent circular ridge, on 

 both sides of which are |)resent longitudinal ridges 

 and grooves. Hooks have a bluntly |)ointed <ipex. 



No fixing muscle or rectal gland 



A. aiignlatm. P. 4.5. 



h. — The two shields show a granular appearance. 

 Hooks two-toothed at apex. The greater part of 



the introvert-surface covered with scattered spines 



A. sj>nia//s. I'. 47. 



CLOŒSIPHON. 



Only one species is known in this coiuitry C. Japoiiicinn. P. 49. 



