of the Subfamily Asterinince. 479 



outer interactinal plates, as stalactites meet stalagmites* ; or 

 they may not join directly, but be united by an intermediate 

 ossicle. In some genera they are differently joined. In typi- 

 cal Asterina, and doubtless in many other genera, if not in all, 

 the genital pores are on the ventral side, in a pair, just outside 

 the jaw plates, but they are seldom visible in preserved speci- 

 mens. The madreporic plate is usually rather large and placed 

 close to the central area of the disk ; sometimes there are two 

 or more, rarely five. The rays vary from five to eight, and 

 some species are probably autotomous. The genus Tremaster 

 Ver. is remarkable for having an oblong perforation passing 

 entirely through the disk in each interradial area, and for hav- 

 ing only one or two furrow-spines. 



The following table shows the classification, now proposed, 

 for the principal generic groups : 



Table of Genera and Subgenera of Aster ininm. 

 I. Interradial areas of the disk not perforated. 



A. Adambulacral spines form a separate comb or combs Avithin 



the furrow edge, and another group on outer surface ; ven- 

 tral plates and interspaces not covered by a granulated dermis. 



B. Principal dorsal plates are all imbricated. 



C. Margins of disk and rays thin, subacute ; rays depressed ; 



usually short. 



D. Interactinal or ventral plates in regular oblique rows, each 



with a fan-shaped group of two to eight small spines, usually 

 webbed. 



E. Dorsal plates of papular areas nearly all of one kind, the 



exposed part usually roundish, elliptical, cordate, or shield- 

 shaped, wholly or partly spinulose. Genus Asterina, in a 

 wider sense. 



a. Two-bladed pedicellarise occur on the dorsal plates and inter- 

 vening dermis. 

 Asterina (restr.) Nardo. Type, A. minuta Nardo=.4. gibbosa 



(Pen. )=verrucidata (Retz.) = A. pulchella Per. Europe. 



act. No pedicellarije present. 



Asterinides Ver., genus nov. Tj^pe, A. folium (Ltk.). W. 



Indies ; see fig. 1, Bermuda ; Florida. 



EE. Dorsal plates of papular areas of two or more diverse kinds, 

 the larger proximally arched or lunate, and notched for 

 passage of papulae ; between these are groups of small 

 ovate or pyriform ossicles inserted endwise, mostly bearing 

 small roundish clusters of spinules. Internal vertical pillars 

 present in interradial areas. 



x. No pedicel lariae found. 



* This feature has been regai'ded hitherto as peculiar to Anseropodinse, 

 but it occurs also in several genera of Asterininae, perhaps in all with thin 

 stiff margins. 



