38-4 Annah of the South African Museum. 



only in deep water and two of the others are tropical stragglers. 

 The five species may be distinguished from each other as follows. 



Key to the South African Species of Echinidae. 



Ambulacral pores in regular arcs of 3 which may however be nearly horizontal. 

 Height of test two-thirds of diameter or more, and may even greatly exceed 

 it; peristome very small, only -15 -25 h. d.; color reddish, with slender red 

 primaries ....... Echinus horridus. 



Height of test rarely three-fourths of diameter and usually little, if any, 

 more than half; peristome moderate or large, "29 -50 of test diameter. 



Gill cuts shallow and not very sharply denned ; size moderate or small. 

 Oculars all exsert; primary spines relatively few and conspicuously 

 longer than the small, rather crowded secondaries ; coronal plates of 

 specimens over 32 mm. h. d., only 15 17; color (of preserved spec- 

 imens) whitish for both test and spines; deep water species 



Echinus gilchristi. 



Ocular I often insert; primary spines numerous, not much longer 

 than the larger secondaries, which are not small and crowded ; coro- 

 nal plates of specimens over 32 mm. h.d., 18 25; color very diver- 

 sified but test at least never whitish; littoral species 



Parechinus angidosus. 



Gill cuts deep and sharply defined; size large Toxopneustes pileolus. 



Ambulacral pores in 3 vertical series, forming very broad poriferous areas 



Tripneustes gro,tilla. 



* ECHINUS HORRIDUS. 



A. Agassiz, 1879. Proc. Amer. Acad., vol. 14, p. 203. Doderlein, 1906, 



VALDIVIA Ech., p. 220; pi. XXVIII, figs. 1-lc. H.L.Clark, 1916, 



ENDEAVOUR Ech., p. 109; pis. XXXIX and XL. 



The VALDIVIA took what seems to be a half-grown specimen of 

 this remarkable urchin in 276 fms. about one hundred miles south- 

 east of Mossel Bay. The species is particularly notable for occurring 

 on the continental slopes of South Africa, southern South America 

 and southeastern Australia. The extra-ordinary vertical height which 

 the adult may attain makes the species doubly remarkable. 



* ECHINUS GILCHRISTI. 



Bell, 1904. Mar. Inv. S. Afr., vol. 3, p. 170. Doderlein, 1906, 

 VALDIVIA Ech., p. 213; pi. XXVI. 



It seems a little strange that the PIETER FAURE met with no 

 further specimens of this species, as there is no specimen in the 

 collection sent me. The full account and numerous figures given by 

 Doderlein make the recognition of the species easy. It was listed 



