104 ECHINOIDEA. 



1. Schizaster fragilis. 



Brissus fragilis, Dub. $ Kor. Vet.- Ah. Hdlg. 1844 (1846). p. 280, pi. x. 



figs. 47 49. 

 Schizaster fragilis, Ag. $ Bes. Ann. Sci. Nat. viii. (1847) p. 22 ; Liitk. 



Vid. Medd. 1863 (1864), p. 175; Al. Ag. Rev. Ech. (1872) pp. 157 



& 363; Mob. fy Butschli, JB. Comm. Kiel, ii. & iii. (1875) p. 150; 



AL Ag. Bull. Mus. C. Z. (1880) p. 85 ; id. Chall. Rep. (1881) 



p. 201 ; id. Mem. Mus. C. Z. x. (1883) p. 74, pi. xxviii. figs. 8-14 ; 



Rathbun, Proc. U.S. Nat. Mus. ix. (1886) p. 291. 

 Schizaster (Brisaster) fragilis, Gray, Cat. Ech. (1855) p. 61. 

 Tripvlus fragilis, Sars, Norg. Ech. (1861) p. 96; Wyv. Thorns. Phil. 



Trans, clxiv. (1874) p. 750. 

 Periaster fragilis, UOrbigny, Pal. Franc, vi. (1854) p. 270; Buj. # 



Hup. Ech. (1862) p. 598. 

 Schizaster cuhensis, Al. Ag. (non D'Orb.) Bull. Mus. C. Z. i. (1865) 



p. 278. 



Anterior ambulacrum not very deep ; antero-lateral ambulacra 

 about three times as long as the poster o-lateral. Highest point of 

 test in hinder third of body, whence there is a steep slope forwards 

 and a very slight slope backwards. Mouth very far in front. 

 General coloration of test in spirit brownish with lighter-coloured 

 spines. 



Length 45 



Greatest breadth 40 



Height 24 



Length of anterior ambulacrum 25 



Length of antero-lateral ambulacrum 



Length of postero-lateral ambulacrum 



The only known British locality is that given by Thomson, " at 

 from 400 to 500 fathoms, between Scotland and Faeroe." First 

 reported from Norway, it has been taken at 50-452 fms. on North 

 American coast, and at 150 fms. in Simon's Bay. From each of 

 these localities the Museum has specimens, but it has no British 

 examples. 



3. SPATANGUS. 



Spatangus (pars), O. F. Midler, Prod. Zool. Ban. (1776) p. 236. 



Vet.-Akad. Hdlq. xi. 7. (1874) pi. xxxvi ; Cams, Prod. faun. Mediter. 

 (1884) p. 102 ; ^Buncan, J. Linn. Soc. xxiii. (1889) p. 251. 

 Echinus (pars), Pennant, Brit. Zool. iv. (1777) p. 58 ; L., Gmel. Syst. 

 Nat. (1789) p. 3168. 



Test large, thin, cordiform, grooved in front, truncated behind ; 

 the paired ambulacra petaloid, broad and sunken, the anterior and 

 posterior pairs almost of the same length ; the anterior ambulacrum 

 in a groove, not well developed. Some of the tubercles much larger 

 than the rest, and carrying long, strong, curved spines. 



The two species have very many characters in common, but 



