ASTEROIDEA 83 



naked spaces may occur also on the distal marginals of balteatus, 

 and it is therefore not safe definitely to declare C. hystrix and 

 Kergroheni to be synonyms of balteatus. The Pentagonaster 

 licesitans Perrier (off Morocco, 2210 m.) also seems very nearly 

 related to, perhaps identical with, C. balteatus ; it bears also much 

 resemblance to Bell's Pentagonaster Greeni. 



2. Plinthaster Verrill. 

 (Syn. Pyrenaster Verrill.) 



Body pentagonal, but the point of the rays may be well marked 

 off from the disk. Dorsal plates naked, with only a circle of grains 

 round the edge. Marginal plates with granules, but naked to a 

 variable extent. Oral intermediate plates covered with granules. 

 Pedicellarise in deep pits on the dorsal and oral interradial 

 plates, sometimes also on the marginal plates. 



Onty one species known from the British seas (and the North- 

 east Atlantic) . 



1. Plinthaster Perrieri (Sladen). (Fig. 46.) 



(Syn. Pentagonaster Perrieri Sladen ; concinnus Sladen ; grandis 

 Perrier; {^ dentatus VerrieT.) 



Rays well marked off from disk ; the last five upper marginals 

 join in the dorsal mid-line. Marginals partly naked, the grains 



Fig. 46. — Plinthaster Perrieri ; oral and dorsal side. Nat. size. 



more or less scarce in their median part. The grains easily fall 

 off, leaving rather deep impressions in the plate. Adambulacral 



