A. M Ver7'ill — Hevision Genera a7id Species of Starfishes. 189 



The jaws are also intermediate, in respect to size, form, and amount 

 of elevation of the actinal ridges, between Mediaster and Plutonaster. 

 The enlarged stellate bases of the abactinal radial paxillae may be 

 considered as a farther development of the slightly enlarged and 

 lobate bases at the columnar paxilliB of Plutonaster. There are no 

 separate, internal, radiating connecting ossicles between the plates, 

 such as exist in Mediaster. At least, I have not found them in 

 anatomical preparations of Pseudar chaster intermedins and Parago- 

 naster formosus, both of which have enlarged six-lobed bases on the 

 paxilliform plates. 



But in Nymj)haster {ternalis) the connecting ossicles are also 

 lacking, and the plates are short-columnar, with the bases only 

 slightly enlarged, thick, and but slightly six-lobed, the lobes being 

 rounded and often indistinct. The same is true, of the correspond- 

 ing ossicles of Posaster. 



Considering all these points, the affinities of the group seem to me 

 rather more with Nymphaster and Mediaster than with any other 

 genera. This is also the view taken by Perrier (1894). 



Pseudarchaster Sladen. Type, P. discus Sladen. 



Pseudarchaster Sladen, 1885, p. 617. Voy. Chall., xxx, p. 109, 1889. 

 Astrogonium (pars) Perrier, Exp. Trav. et Talism., p. 338, 1894 (not of M. 

 and Troschel, nor of Gray). 



The principal characters of this genus have been mentioned in the 

 above description of the subfamily. 



The adambulacral plates have a divergent or palmate series of 

 furrow spines and a group or radiant cluster of actinal spines. The 

 actinal plates are generally closely covered with small appressed 

 spinules, often somewhat squamiform, rarely elongated, but fre- 

 quently a few larger spinules exist among the smaller ones. Lower 

 marginal plates are usually spinulated like the actinals, rarely granu- 

 lous, often with one or more central rows of larger appressed 

 spinules. 



Specialized fascioles usually (but not always) exist between more' 

 or less of the larger actinal plates, especially toward the jaws. The 

 ambulacral feet have well formed suckers. 



The abactinal plates and upper marginals are usually closely 

 granulated. More than one series of abactinal plates usually extend 

 nearly to the ends of the rays. 



Perrier united Ap?iroditaster with this genus, but the type seems 

 to me sufficiently distinct. However, the presence or absence of the 



