100 



BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



the gononxl facics, structure of marginals, characteristic terminal plate, and the 

 tall slentler paxilla;, as well as the characteristic furrow armature to determine 

 the species. 



Type— C&t. No. 24G75, U.S.N.M. 



Type-locality.— Albatross station 3.347, off (^ascadc Head, Oregon, 345 fathoms, 



mud (2). 



Distrihution.—Washmgton to vicinity of San Diego, California, and between 



300 and 800 fathoms, usually on mud. 



Specimens examined.— Voriy-iive specimens, including type, from the foUowmg 



stations: , . , 



Specimens of Dipsacastcr anojHus examined. 



2925. 

 2937. 

 2980. 

 3075. 

 3347. 

 4317. 

 43S1. 

 4380. 



4407. 

 44 is. 



4416. 

 4427. 



Locality. 



Between Santa Catallna and San Clemente 



Islands, California, 

 on San Dlcgo, Calilomla 



.do. 



South of Santa Cruz Island, California. 



Off Sea Lion Kock, Washmgton 



Ofl Cascade Head, Oregon 



Off San Diego, California 



.do. 



Near Los Coronados Islands, Lower Cali- 

 fornia. 



Between San Clemente and Santa Catallna 

 Islands, California. 



do 



Between Santa Catallna and Santa Barbara 



Islands, California. 

 Between Santa Barbara and San Nirholas 



Islands, California. 

 OS Santa Cruz Island. California 



161^10 

 423-4S8 

 530-«38 



334-000 

 C38-302 



Nature of bottom. 



gray sand . 



mud 



green mud . 



mud 



fine gray sand, green mud. 



green mud 



gray sand, green mud 



green mud . 



rocks, shells, fine gray sand, 

 green mud 



dark green mud. 



475-510 green mud. 



U. S. Nat. Mus. 



Albatross, 1904. 



Remarks. — ^This species bears a striking resemblance to Leptychaster (for 

 instance a form about intermediate in external appearance between L. anomalus 

 and L. pacificus) ])rincipally on account of the unarmed marginals and the general 

 facies of the actinal surface. The structure of the gonads, character of paxilise as 

 well as the distribution of papulae and presence of a conspicuous anal aperture 

 remove the species from that genus. At the same time it must be admitted that 

 its relegation to Dipsacaster is open to criticism. The marginal plates, especially 

 the inferomarginals are unlike those of Dipsacaster, and the absence of paj^ulse from 

 the center of disk is an Important difference. The madreporic plate is relatively 

 smaller than in typical Dipsacaster, and although hidden, only one or two paxillae 

 arise from its surface, instead of many. The general form of the paxillae, form of 

 intestinal coecum, well developed anal aperture, and distribution of gonads have 

 been the characters which have led me to place the species in Dipsacaster. The dis- 

 tribution of gonads would prevent tlie species being ranked under either Patagiaster 

 Fisher or Leptychaster Smith (including Parastropecten) . Ludwig's genus is founded 

 upon evidently immature specimens. 



The present species undoubtedly brings Dipsacaster much closer to Leptychaster, 

 and it may be regarded as an extremely aberrant member of the former. 



