198 



PAXAMK! DEEP SEA ECHINI. 



Station 3399, off Galera Point, in 1740 fathoms. Lat. 1 7' N. ; Long. 

 81° 4' W. Bottom temperature, 36°. Gn. ooze 



Bathynietrical range, 1175-1772 fathoms. Temperature range, 36 .8- 



35°.8. 



SPATAGODESMA A. Ag. 

 Spatagodesma A. Ag., Bull. M. ( !. Z. 1898, XXX11. No. 5, p. 83, Plate XII, fig. 8. 



During the voyage of the "Albatross" from New York to San Francisco 

 ( L887 to 1888) there were obtained from Station 2709 a few specimens of a 

 small Spatangoid (PI. 107, fig. G) with a peculiar apical fasciole differing 

 widely from that of any Spatangoid known to me, Fig. 284. 



A broad elliptical fasciole encircles both the ambulacra and the anal 

 system (PI. 107, fig. ■'•'). A transverse band, convex posteriorly, divides the 

 fasciole into two areas, one enclosing the anal system (PI. L07, figs, g, 5), 

 but not in any way corresponding in shape or position to an anal fasciole, 

 the other becoming a peripetalous fasciole. 



Fig. 2S4. Spatagodesma. 



16 Him. 



Fig. 285. A. excentrica. 



The nearest approach to the fasciole of this genus is found in Agassizia 

 (PL 108). To facilitate the comparison between these genera I have given 

 figures of the young of two specimens of Agassizia ; one 5 mm. in length 

 (PI. 108, figs. 1-5), and the other 16 mm. (PI. 108, figs. 6-9)? It will 

 be noticed that in the smaller Agassizia the ambulacral plates within the 

 fasciole do not yet possess double pores (PI. 108, figs. ~, 3, 5), and that the 

 phyllodes are not yet developed round the actinal system (PI. 108, fig. 1), 

 though in this small specimen, the course of the lateral fasciole and its peri- 

 petalous branch (PI. 108, figs. /-',) shows but slight variation from that of an 

 older specimen of 1G mm. in length, Fig. 285 (PI. 108, figs. GS), the princi- 

 pal difference being in the course of the subanal branch of the lateral fas- 



1 "Blake," 1878-79, St. ■_ , :!1 off St. Vincent, 95 fathoms 



