268 PEOF. P. M. Duncan's eetision or the 



Solaster. The flat actinal surface and the globular outline 

 remind that author of Cardiaster, but the actinostome is more 

 central than in Cardiaster. 



Loven, ' Pourtalesia,' p. 60, notices that Genicopatagus, in 

 common with the other abyssal genera, is apetalous ; the ambu- 

 lacra are flush with the test, and only contract up to the top. 

 The plates are few, as high as they are broad, or nearly so, are 

 regularly hexagonal ; the pores are very miuute, and placed cen- 

 trally or subceatrally, and the pedicels are small and simple. 

 The description given by Loven (p. 76) of the apical system of 

 Genicopatagus affinis, A. Ag., we have taken to be generic in 

 preference to the delineation and description given in tlie ' Chal- 

 lenger ' B-eport, for it is probable that the specimen therein 

 described was imperfect. 



Genus Pal^obeissus, A.Agassiz, 1883, 'Report on ^BlaTce' Exped. 

 Ech., Mem. Mus. Camp. Zool. Harv. vol. x. no. 1, p. 56, 

 pi. xxiv. 



Test moderate in size, ovoid in marginal outline, widest an- 

 teriorly ; narrow and truncated posteriorly ; tumid but depressed 

 dorsally, more or less flat actinally, projecting downwards 

 posteriorly. 



Apical system excentric in front, at th.e vertex, small, compact ; 

 four basal plates in contact; the genital pores small iu the 

 anterior pair and large in tlie posterior basal plates; radial 

 plates small. 



Ambulacra diverse, flush, apetalous ; the anterior with small 

 distant pairs of pores ; the paired ambulacra widely open at the 

 ambitus, increasing in breadth from the apex, the pairs wide 

 apart, few, the pores large and circular, remote from tlie apex, 

 actinally iu peripodia. 



Interradia with numerous plates, with distant primary tu- 

 bercles, small and of uniform size, but increasing towards the 

 ambitus ; miliaries between ; primary tubercles closer actinally, 

 but the ambulacra are bare. 



Peristome semilunar, excentric in front, labrum projecting; an 

 amphisternum. Periproct circular, low down in the posterior 

 truncation. Tentacles of the abactinal pores broad, flat, and with 

 small disks, the actinals fimbriated. 



Primary spines small, slender, straight ; miliary spines one 

 third of tlie length of the others; short-stemmed, stout-headed 



