STARFISHES OF THE PHILIPPINE SEAS. 215 



Remarks. — Although this species is close to both B. vlolaceus and 

 B. polyctenius, its characters seem to warrant its separation. It 

 differs from B. violaceus in having numerous abactinal pedicellariae, 

 larger interradial superomarginal spines, no accessory superomar- 

 ginal spines, rather fewer abactinal spinelets, and fewer adambu- 

 lacral plates to the first 10 inferomarginals. That styracius is a race, 

 of violaceus is quite within the range of possibility. 



As the foregoing description is largely in the form of a comparison 

 between polycfenius and styracius nothing further need be added. 



Family RADIASTERIDAE Fisher. 



Mimasterivac Sladen, 1889. p. 331.— Fisher, IQUd, j). JGl. 

 Mimasteridae Vekrill, 1914a, p. 282. 

 Radiasteridae Fisher, 1916a, p. 4. 



Diagnosis. — Phanerozonia, with small, subequal. subpaxilliform 

 marginals, resembling the Astropectinidae abactinally and the Ga- 

 neriidae actinally, but with sucking disks on the tube feet and com- 

 plete membranous interbrachial septa, and superambulacral plates; 

 abactinal skeleton consisting of penicillate, usually independent, 

 paxillae ; actinal plates imbricated in transverse series, tabulate, with 

 a coordinated tuft of spinelets ; adambulacral armature a coordinated 

 tuft of spinelets increasing in length toward the tAvo or three almost 

 undifferentiated furrow spinelets; first adambulacral somewhat com- 

 pressed ; mouth plates rather astropectinoid, with a straight or angu- 

 lar marginal series of spines, with or without an unpaired median 

 spine at the inner angle. 



Remarks. — In respect to its systematic position Mimasfer Sladen 

 has been a rather restless genus. Sladen recognized its curious com- 

 bination of apparently incompatible characters and made it the type 

 of a subfamily of the Pentagonasteridae. It has been variously re- 

 garded as belonging to the Archasteridae (Perrier, 1894), Plutonas- 

 teridae (Verrill, 1899), and Goniasteridae (Fisher, 1911^^), until re- 

 cently it was dignified by being raised to family rank (Verrill, 1914). 

 Professor Verrill's disposition seems to be the best way out of the 

 difficulty. 



Since the publication of the Asteroidea of the North Pacific, I have 

 had the opportunity of examining two true Mimasters, M. tizardi 

 Sladen, and M. notabilis Fisher, as well as the M. cognatus of Sladen, 

 which appears to be generically distinct. 



The abactinal skeleton of MiTruuter is strongly astropectinoid, the 

 plates being typical penicillate paxillae, but the marginals, while 

 perhaps neutral, remind one strongly of the marginals of Cycefhra., 

 ;! resemblance heightened by the actinal and adambulacral armature, 

 which is decidedly ganeriid. By having definite sucking disks on 



