472 PROCEEDINGS OF THE NATIONAL MUSEUjM vor>. 86 



that of liifafa except th;il the spines are not grooved and liave a 

 somewhat heavier sheath. 



The adambulacral spines are narrowly spatidate, -with subparalle] 

 sides, rounded tip, and sometimes a sliglit concavity of the terminal 

 part but not a marked groove. Tlie rather thick slieath, however, 

 has a well-marked groove for the whole length of the outer side, but 

 the spine itself is not gouge-sliaped as in hr-ftaf". The furrow spine 

 is set on the furrow face of plate at a slightly lower level than the 

 subambulacral, and on proximal plates measures 4.5 mm while the 

 slightly more robust subambulacral is 5 to 5.5 mm. 



The mouth plates have 4 (or 3) marginal and 1 suboral spine; 

 the imier marginal is truncate, shallowly grooved, and 5 mm long; 

 the next 3 are successively shorter, the outermost being 2.5 mm. 

 All have rather heavy sheaths. 



Type.—V. S. N. ^f. no. E. 5603. 



Tijpe locality. — Albatross station 5040. off Honshu. Japan, lati- 

 tude 38^12' X.. longitude 142°02' E. ; 182 fathoms; dark gray sand, 

 broken shells, Foraminifera : bottom temperature 37.8° F. ; one 

 specimen. 



Remarkf!. — This specimen w;i^ uientionod by me (1011, p. 264) in 

 connection with an account of P. /n.-flata. T have recently studied a 

 specimen of P. echinaMev Perrier from Gougli Island. This speci- 

 men lacks any trace of dermal spinelets. It has numerous perforated 

 embr3"onic plates much smaller and simpler than those of hifata and 

 comparable to the first stages of the ]-)latelets of japonira. P. 

 ecMnafiter has 2 inferomarginal spines over part of the ray, very 

 few actinal spines, while the adambulacral spines (occasionally 3) 

 are flattened, spatulate, and not grooved. P. rapensist H. L. Clark 

 is probably only a race of crhinaster. P. mira (de Loriol),^ from 

 Gulf of San Mathias. Argentina, differs in having shorter tiibercular 

 abactinal spines oft^n with a capitate tip, and, in addition to the 

 spines, the surfac<> of body is covered by a multitude of almost 

 microscopic thorny spinelets. larger and much more numerous than 

 those in japonina. 



T.TTERATURE CITED 



FisHEn;. Walter Kbtnrick. 



Iflll. Astprnidoa of flio North Pnrifio nnd adj-irrnf wntoiis. T". S. Nnt. Mus. 

 Bull. 70. pt. 1. 4in rP- 1-2 Ills. 



I.ORIOI,. PEn?rEVAL DE. 



1004. Notes pour sorvir a IV-tude des (V-hinodorniPS. .«or. 2. fasr. 2. 68 pp.. 

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