THE GEPHYREA OF JAPAN. 43 



to a point on the left of the nerve-cord and cdose to it, far more 

 antei'iorly than the root of the retractor nuiscle on the same 

 side. The segmental organs {so) are remarkably long, being 

 equal to two-thirds of the length of the body proper. The organs 

 are fixed throughout their whole length to the body-wall by a 

 mesentery. The tentacles are short and thick, numbering 8-10. 

 Two eye-spots are present on the ganglion. 



Among the hitherto known Aspidosiphon species, A. elegans 

 Cham. & Eisenh. seems to be most closely allied to the present 

 species. However the two species in question may be distinguished 

 from each other by different features of the anal and caudal 

 shields and by the difference in the size and form of the hooks 

 and spines. 



Habitat : I have collected the species only at Misiiki, along 

 rocky shores in the vicinity of the Marine Laboratory. 



ASPIDOSIPHON UNISCUTATUS, n. sp. 



(Figs. 10, 73 — 77). 



The unique specimen (shown in Fig. 10) on which this 

 species is based, was found in Mr. Miyajima's collection made 

 at Kataura in the province of Satsuma (1900). In its present 

 state, preserved in alcohol, the body proper measures 13.5 mm. 

 in length and 3.5 mm. in maximum width. The skin, which 

 is relatively thick, is yellowish brown becoming a deeper brown 

 towards the anal shield. The latter, deep reddish brown in 

 color, is of a tall helmet-like shape, obliquely truncated at the 



