MONOGEAPH OF JAPANESE OPHIUROIDEA. 97 



cliondreUa squamosa (Lyman) are quite like those of Ophiolehes. 

 Taking all the characters into consideration, Ophiolehes, Ophiosemnotesy 

 OpMochondreUa, Ophiocamax, &c. appear to me to represent one 

 of the two types of the Ophîacanihidœ. 



Key to Japanese genera of Oiyhiacanthidce, 



A — Tentacle pores very large and open ; oral shields entirely separated 



from the first lateral arm plates by the adorai sliields. 

 a — Disk extraordinarily bulged up, covered with fine scales ; radial 

 shields absent ; numerous large, flat, spatulate oral papillae ; numerous 



flattened arm spines ; tentacle scales spatulate Ophiomyces. 



aa — Disk not very high. 

 h — Disk finely imbricated, entirely free of granules or spines ; tentacle 



scales present, 

 c — Outer oral papilla) not especially long ; ventral arm plates longer 

 than wide ; three arm spines ; two very small, leaf -like tentacle 



scales OpJdologimus, 



cc — Outermost three oral papillaa very long, slender, spiniform, arising 

 from the adorai shields; ventral arm plates wider than long; four 

 arm spines ; three or four spiniform tentacle scales .... Op>Iiiophrura, 



lib — Disk closely beset with granules or spines. 

 d — Dorsal arm i)lates entire; no tentacle scales. .......... . Ophiopora. 



dd — Dorsal arm ^jlates absent, dorsal side of arms, as well as disk, being 

 closely beset with spines ; three or four spiniform tentacle scales . . 



Ophiambix 



A A — Tentacle pores small and inconspicuous. 



e — ^Ajm plates and arm spines not covered over by a cereous skin. 

 / — Radial shields small or moderate. 

 g — Radial shields short, rounded or triangular. 



h. — ^Disk closely covered with granules ; oral shields separated from the 

 first lateral arm plates by the adorai shields ; oral angles beset with 

 granules ; outermost oral papilla large and operculiforra . . OphioUrmia. 



