202 THE VOYAGE OF H.M.S. CHALLENGER. 



Atlantic, a,s the accompanying widely-separated localities where it was collected by the 

 Clialleno-er indicate. 



Station 49. May 20, 1873. Lat. 43° 3' N., long. 63° 39' W. ; 83 fathoms ; bottom 

 temiJerature, 1'8° C. ; gravel, stones. 



Station 142. December 18, 1873. Lat. 35° 4' S., long. 18° 37' E. ; 150 fathoms; 

 bottom temperature, 8 "3° C. ; sand. 



''Schizaster japonicus (PL XXXVI. figs. 8-13 ; PL XLIII. fig. 26 ; PL XLV. 

 figs. 7-10). 



Scliizaster jajMiiicus, A. Agassiz, 1879, Proc. Am. Acad., vol. xiv. p. 212. 

 In this species the posterior lateral ambulacra (PL XXXVI. fig. 11) form a more 

 acute angle with the longitudinal axis than in Schizaster ventricosus ; it has also a very 

 distinct latero-anal fascicle (PL XXXVI. fig. 12), a smaller anal opening, and a more 

 pointed posterior extremity. A prominent keel in the median posterior interam- 

 bulacrum forms a high crest at that end of the test (PL XXXVI. fig. 12), while 

 Schizaster ventricosus is remarkable for its comparatively flattened and rounded 

 posterior extremity (PL XXXVI. figs. 1, 3). 



The ambulacra are all more deeply sunken, much as in Schizaster cancdiferus and 

 Schizaster fragilis. The test is highest immediately behind the apical system in the odd 

 interambulacrum (PL XXXVI. fig. 12). These characters are early developed, as a 

 comparison of young specimens of Schizaster ventricosus and Schizaster jcqw7iict(s, 

 measuring respectively one-third and half an inch in length, readily shows. The 

 peripetalous fasciole is broad, and made up of triangular-shaped l^ands at the angles, and 

 especially at the points in the median ambulacral spaces ; it runs nearly straight across 

 the odd interambulacrum from the extremity of the posterior petals. 



There are two large genital openings in the posterior lateral ambulacra and a minute 

 one in the left anterior one, while in Schizaster ventricosus these three are equally 

 developed (see Revis. Ech.). The apex is also more central in this species, and the 

 peripetalous fasciole less angular than in Schizaster ventricosus. The lateral fasciole 

 (PL XXXVI. fig. 1 2) extends under the anus, it is narrow and sharply marked ; the 

 posterior ambulacra are proportionally wider, the outline more angular, the test swollen, 

 and pointed at the posterior extremity when seen from above (compare PL XXXVI. 

 figs. 11 and 12). 



This form of Schizaster, and such forms as Moiropsis claudicans, readily pass on 

 the one side into Moira, with its still more deeply sunken ambulacral plates, and 

 comparatively ovoid and angular test, and into those fossil species of Schizaster, which 

 have generally been associated with Linthia. 



It is interesting to note with reference to the development of the fascioles, that in 

 a young specimen measuring 12 mm. in length the lateral fasciole is indistinct near its 



