210 VERRILL 



Cribrella FORBES, Brit. Starfishes (as Cribella), 1841 (non Agassiz). L. 

 Agassiz (pars), Prod., in Mem. Soc. Sci. Nat. Neuchatel, i, p. 191, 1835. 

 Liitken, Gronl. Echinod., p. 30, 1857. Norman, Ann. and Mag. Nat. Hist., 

 xv, p. 124, 1865. Verrill, Proc. Boston Soc. Nat. Hist., x, p. 345, 1866. 

 Perrier, Revis. Stell. Mtis., Arch. Zool. Exper., rv, p. 373, 1875. A. Agassiz, 

 North Amer. Starfishes, p. 113, pi. xvm, 1877 (structure of skeleton). 

 Viguier, Squelette des Stell., Arch. Zool. Exper., vn, p. 126, pi. vn. 

 figs. 8-15, 1878 (odontophore). Sladen, Voy. Chall., xxx, p. 540, 1889. 

 Perrier, Exp. Trav. et Talism., p. 143, 1894. Ludwig, Fauna Arctica, p. 

 473- 



Form usually neatly stellate with slender terete rays ; sometimes 

 with short rays. 



Dorsal ossicles small, convex, closely united or overlapping at the 

 edges, and arranged in a reticulated or areolated pattern, leaving 

 small papular areas, carrying few, often single, papulae, and not cov- 

 ered with a thick integument. Dorsal spines minute and nearly uni- 

 form, crowded in divergent clusters on the convex ossicles, both on 

 the dorsal and lateral surfaces. Adambulacral spines in transverse, 

 usually double rows, or in multiple clusters of small graded spines 

 on the outer side of the plates ; the inner spine is compressed and 

 inserted within the margin of the groove as a furrow-spine; some- 

 times two are present in the grooves. 1 



Superomarginals small, often indistinct and like the dorsals. 

 Inferomarginal plates small, but distinct, often larger than the 

 superomarginals, contingent with the latter distally, but separated 

 proximally by one, two, or more rows of interpolated marginal 

 ossicles, varying in number and extent, and thus causing great 

 variations in the thickness and taper of the rays. Peractinals and 

 inferomarginals similar and closely joined, convex, and covered with 

 small spinules, the rows separated by papular pores; the papulae 

 may occur also between the peractinals and adambulacrals. 



Pedicellariae have not been observed in any species. The eggs and 

 young are carried under the oral region. 



The madreporite is generally covered with spinules like those on 

 the other dorsal plates. 



The West Indian species, H. antillarum (Perrier, as Cribrella), 

 has six rays and two madreporites. It appears to be autotomous. 



1 A new genus, HENRICIDES, is now proposed for Henricia heteractis Clark 

 (op. cit, 1909, p. 530, pi. XLIX, figs. I, 2), from Australia. 



It has six or seven rays, multiple madreporites, and is probably autotomous. 

 Dorsally it is like Henricia. It has no furrow-spines ; the outer side of the 

 adambulacral plates bears a marginal row or comb of five or six spines pro- 

 jecting over the furrow, and back of these a group of divergent spines. 



