322 VERRILL 



Fasciolated grooves extend between the adambulacral and most of 

 the interactinal plates. Jaws are very prominent on the actinal sur- 

 face and bear numerous peroral and adoral spines on the sides and 

 summit. The lateral peroral spinules are fasciolated; the actinal 

 groups or rows are connivent. 



This genus is undoubtedly closely allied to Blakiaster, Persephon- 

 aster and Leptychaster, especially to the two former. 



Dr. Fisher thinks (op. cit., 191 ib, p. 40) that it ought to be united 

 with Blakiaster, which he carefully describes from the type. I have 

 also studied the same type. It differs from that genus, however, in 

 the less massive and differently shaped marginal plates, which are 

 less complex and have more fully developed fascicles. The lower 

 marginals have the spines in a central row or group, not submar- 

 ginal. There is no differentiated median radial series of dorsal 

 ossicles ; nor any notable number of secondary ossicles, so evident in 

 Blakiaster; nor any median radial area destitute of papulae, as in the 

 latter. There are well defined fascioles between the adambulacral 

 and interactinal plates, not found in the latter ; and the adoral adam- 

 bulacral spines are deeply sunken in the groove, as in Persephon- 

 aster, but not in Blakiaster (type, B. conicus Perrier). 



The abactinal plates are thinner, more regularly stellate, and more 

 delicately articulated by the slender radial lobes than in the latter, 

 so that the test is more flexible. In Blakiaster the lobing is irregular 

 and the edges overlap. 



In many of these characters it is nearer to Perse phonaster, but 

 the latter lacks the odd interradial interactinal plates, found in this 

 genus and in Leptychaster. 



From the latter it differs in the characters of the abactinal 

 ossicles, in the less profoundly fasciolated grooves between the 

 marginal plates, and in other characters ; but it is perhaps as nearly 

 allied to the latter as to Blakiaster. 



It is, in fact, a sort of connecting-link between these three genera. 

 Possibly it may eventually be desirable to unite it with Leptychaster 

 and Blakiaster in one larger genus, should more connecting species 

 be discovered. 



BUNODASTER RITTERI Verrill. 

 Plate LXXXVI, figures i, ia (details) ; plate civ, figures i, 2 (type) ; plate cv, 



figures i, 10 (type, enlarged) ; text-figures Nos. 15, 16. 

 Bunodaster ritteri VERRILL, op. cit., XLIII, p. 554, fig. 4, 1909. 



Rays five, regularly and rapidly tapered, slender, subacute; neatly 

 stellate. Disk rather thin, flat, about as wide as the length of the 



