SHALLOW-WATER STARFISHES 205 



the peculiar characters of the group. The Velata must, however, be 

 regarded as a highly specialized group, or suborder, differing in 

 many respects from all other starfishes. The Pythonasteridae seem 

 to me more nearly allied to Solasteridae. 



The family Valvasteridae, referred to Spinulosa by Fisher, seems 

 to me to belong rather to Valvulosa, among the Phanerozona. It is 

 not represented on the west coast. 



Family ECHINASTERIDJE Verrill (restricted). 



Echinasteridce Verrill (pars), Trans. Conn. Acad. Sci., i, p. 343, 1867. Per- 

 rier (pars), Revis. Stell., Arch. Zool. rv, pp. 299, 358, 1875. 



Echiniasterina Vicuier, Arch. Zool. Exper. et Gen., vn, p. 123, 1878 (struc- 

 ture). 



Echinasteridce Sladen (pars), Voy. Chall., xxx, p. 535, 1889. Bell, Catal. 

 Echinod., pp. 23, 95, 1890. Perrier, Etoiles de mer, Nouv. Arch. Mas. 

 Nat. Hist., VI, p. 164, 1884; Exp. Trav. et Talism., pp. 28, 141, 18^ Lud- 

 wig. Fauna Arctica, i, p. 472, 1900. Fisher, op. cit., 1911&, p. 258 (analyt- 

 ical table of known genera, p. 259). 



Dorsal skeleton usually fonned of small, sometimes overlapping, 

 reticulated or areolated ossicles; sometimes they form longitudinal 

 radial rows. Median dorsal row is often indistinct. Upper mar- 

 ginals small, often not specialized. Inferomarginals usually distinct. 

 One or more interactinal rows are usually present. Dorsal and 

 marginal spines may be large and isolated or minute and clustered, 

 but not truly paxilliform. They are often covered with a distinct, 

 thick, dermal membrane, which may contain calcareous granules. 



The ambulacral ampullae are usually single, one to each tube-foot. 



Ambulacral grooves narrow. Adambulacral spines small, two or 

 several to a plate, either in longitudinal or in transverse groups. No 

 pedicellariae known. 



The mo.st prominent genera are Echinaster and Henricia, both of 

 which occur on the Northwestern coast. 



Genus Poraniopsis Perrier. 



Poraniopsis Perrier, op. cit., 1891, p. 105, pi. x, figs. 20, 2b (type P. echinaster 



Perrier). Fisher, 1910, p. 568; 19116, p. 260. 

 Lahillia de Loriol, 1904, p. 32. pi. iii, fi^s. l-lg (preoccupied). 

 Alexandraster Ludwig, 1905, p. 210, pi. XV, figs. 79, 80; pi. xxxr, figs. 



181-183; pi. xxxii, fig. 184. 

 Ortmannia de Loriol, op. cit., 1906, p. 78. 



Form is five-rayed, stellate. Surface covered with a thick skin. 

 Abactinal ossicles spinose, slender, forming an open reticulation with 



