SCHIZASTER TOWNSENDI. 



207 



Fig. 299, and S. canaliculata, Fig. 300, with only slight variations in the 

 dimensions of the right anterior genital, the madreporite, or in the atrophy 

 of one or more genital pores. 



Station 3431, off Altata, Gulf of California, 995 fathoms. Lat. 23' 59' N. ; 

 Long. 108° 40' W. Bottom temperature, 37°. Lt. br. m. glob. 



Fiu. ayy. s. i'kagii.is. 



Afteh Loven. 



Fig. 300. S. canaliculata. 

 Aftee Loven. 



Schizaster Townsendi A. Ag. 



Schizaster Townsendi A. Ag., Bull. M. C. Z. 1898, XXXII, No. ;"., p. 82, PL XI, figs. 2, 3. 1 



Plates 100, figs, is-, 101. 



In young specimens the apical system is comparatively more distant from 

 the posterior extremity than in older specimens. In two specimens, measur- 

 ing 10 and 11 min. in length (Pis. 100, fig. 1\ 101, fig. 7), the apical system 

 was central. In a somewhat larger specimen, 15 mm. long, the apical system 

 was G mm. from the posterior edge, showing that the anterior extremity 

 develops more rapidly with age than the posterior, the lateral anterior 

 ambulacra soon far outstripping in length the posterior ones. In a specimen 

 of 22 mm. in length the centre of the apical system was 8 mm. from the 

 posterior extremity. In a specimen of 32.5 mm. the centre of the apical 

 system was 13 mm. from the posterior extremity, 14 mm. in a specimen of 

 36 mm. in length, and 15 mm. in the largest specimen collected, of 49 mm. 

 A distinct thin anal fasciole extends across the posterior interambulacrum 

 (PI. 101, fig. 7). This species is marked by the flatness of the test (PI. 100, 

 figs. 4, 3), the great width of the lateral ambulacra (Pis. 100, fig. J; 101, 

 fig. ..'), the small size of the anal system (PI. 100, fig. 5; 101, figs. ,-?, 7), the 

 close primary tuberculation of the actinal plastron, which is in striking con- 

 trast to the bare actinal surface (Pis. 100, fig. .?; 101, fig. 1). 



1 Referred to S. latifrons l>y mistake in Dull. M. C. Z. 1898, XXXII, No. 5, p. 81. 



