1887.] PROCEEDINGS OF UxNITED STATES NATIONAL MUSEUM, 449 



i^n;^"T.^^'ir ^' '^V'^'' "'^'""^ "^"""^^ Pl^^^^^' occasionally more dis- 

 tant. The three median rows form a broad series, of which the individ- 

 ual rows are generally distinct, sometimes very regular and well sepa- 

 rated, at others irregular and more or less intermingled. Close by the 

 disk proper they become reduced to a single row. On the innerpart of 

 the rays they consist, mainly, especially the median row, of large spines, 

 simdar to those of the disk, but the spines gradually decrease i^ size 

 and become very small and short toward the tips of the rays The mad 

 reporic plate is near the margin of the disk, and is generally very irreg- 

 ular m shape. -^ ^ '^^^^te 



The adambulacral spines are comparatively small, numerous, cylin- 

 drical, or slightly compressed. The ventral spines are much larger 

 more distant y separated, stout, more or less compressed, varying in 

 shape from slightly tapering to slightly clavate. Between the adam- 

 bulacral row and the lateral abactinal row above described there are 

 generally four regular rows, including the ventral series. The two upner 

 rows are regular and consist of smaller spines than the ventral, resem- 

 bling more those of the upper surface. The actinostome is re ativeTy 

 small compared with that of the other species. 



RECORD OP SPECIMENS IN THE COLLECTION. 

 Lower California : 



La Paz , L. Belding (15396); A. Forrer (10025). ' 



Pichihiego Bay (3628). 

 Mexico : 



Mazatlan ; A. Forrer (10024). 



Puerto Balandra, Gulf of California; W.J. Fisher (8956). 

 Chatbam Island, Galapagos Islands; Dr. W. H. Jones, U. S. N. (12653) 



PROC. N. M. 87—29 



