530 Crustacea and Echinodermata of the 



ASTEKISCUS MINIATUS. Brandt. 



Asterias miniata, Brandt ; I. c. 68. 



This pentagonal star-fish may be readily distinguished 

 by its thin disk and sharp edge. 



Hab. Sitka, (Mertens ;) Tomales Bay, (Satnuels ;) San 

 Francisco, (Ay res ;) Island of San Miguel, (Trowbridge.) 



MEDIASTER ^EQUALIS. Stimpson. Nov. gen. et sp. 

 PI. XXIII. f. 1, 8, 9, 10, 11. 



This name is proposed for a Goniastroid star-fish, com- 

 mon on the coast of Oregon and California, which I can- 

 not refer to any described genus or species, although it is 

 not impossible that it may belong to one of the numerous 

 genera of J. E. Gray, which are however so imperfectly 

 characterized that it is extremely difficult, if not impossible, 

 to identify them. 



Body of little thickness, flat above and below ; five- 

 rayed ; length of rays equalling or exceeding the diameter 

 of the disk. Skin set with numerous small rounded plates, 

 nearly uniform in size but becoming somewhat smaller 

 toward the margin ; they are rather more crowded below 

 than above. Scattered pores on the surface of the skin 

 between the plates. Margins with a double row of large 

 quadrangular plates ; those in the upper and lower series 

 opposite. All of the plates above and below, including the 

 marginal ones, are covered with granules nearly uniform 

 in size and easily rubbed off. On the lower surface the 

 granules are somewhat larger and angular, and those on 

 the plates bordering the ambulacral furrows are elongated 

 so as to form subprismatic spines, eight or ten to each 

 plate, the inner ones largest. Anus central, surrounded 

 by a circle of spine-like granules. No pedicellariae or 

 "two-lipped pores," excepting a single one in the centre 



