172 ECHINOIDEV. 



ambulacrum not in a groove, spines fine and delicate. Upper part 

 of test nearly level from hinder end to the anterior border of the 

 internal fasciole, and then sloping gradually downwards ; the anus 

 is slightly overhung by the upper part of the test ; the internal fas- 

 ciole is well marked and is almost triangular in form, its hinder 

 part is only one or two plates behind the madreporite ; the number 

 of well-marked pores is, in the front antero-lateral series five or six 

 and in the hinder nine or ten ; the outer postero-latoral series has 

 seven and the inner six ; but, as before, too much importance must 

 not be given to the constancy of these numbers ; all the ambulacra 

 are flush with the test. 



The long axis of the oval periproct is at right angles to a vertical 

 line ; the subanal fasciole contains one or two pairs of pore-bearing 

 plates ; the bare ambulacral spaces below are very wide ; the tuber- 

 culatum is coarser at the sides and below than it is in the median 

 part of the dorsal surface. 



Length. Breadth. Height. Peristome. 



34 33 23 7 



24 20-5 16 5-5 



Distribution. Atlantic from Norway to Cape of Good Hope ; 

 North Sea; Coast of Florida ; Mediterranean. 5-140 fms. 



a, b. 59° 34' N., 7° 18' W., 542 fms. < Porcupine ' Exp., 1809. 



c, d. Port Erin, Isle of Man. Prof. Herdman. 



e, f. Shetland. E. M< Andrew, Esq. 



5. BEISSOPSIS. 



Brissopsis, Ay. Cat. Syst. Ectyp. (1840) p. 16 ; Ay. et Des. Ann. Sci. Nat. 



viii. (1847) p. 14; Desor, Syn. Ech. foss. (1858) p. 378; Al. Ay. 



Rev. Ech. (1872) pp. 95 & 354 ; Dune. $ Sladen, Pal. Ind. xiv. 3. 



(1884) p. 202 ; Dune. J. Linn. Soc. xxiii. (1889) p. 248. 

 Brissus, Forb. Brit. Star/. (i841) p. 187. 

 Brissiopsis, Gray, Cat. Brit. Had. (1848) p. 7 ; id. Cat. Ech. B. M. 



(1855) p. 55. 

 Kleinia, Gray, Ann. # May. vii. (1851) p. 133 ; id. Cat. Ech. (1855) 



p. 48. 

 Toxobrissus, Des. Syn. Ech. foss. (1858) p. 399. 

 Deakia, Pavay, Ma'yyar foldt. intezet. Budap. Evk. iii. (1874) p. 304. 

 ? Verbeekia, Fritsch, Palceontoyr. Suppl. iii. 1. (1877) p. 92. 



Test never large, rather thin, oval, somewhat compressed from 

 side to side, truncated behind but not highest there; the paired 

 ambulacra subpetaloid and sunken, the anterior pair as long or 

 longer than the posterior. Anterior ambulacrum slightly sunken. 

 Spines moderately stout. 



1. Brissopsis lyrifera. 



Brissus lyrifer, Forbes, Brit. Starf. (1841) p. 187 ; Diib. $ Kor. Vet.- 

 Akad. Hdly. 1844 (1846), p. 280, pi. x. fig. 46; Thompson, Nat. 

 Hist. Irel. iv. (1856) p. 442. 



Brissopsis lyrifera, Ay. fy Des. Ann. Sci. Nat. viii, (1847) p. 15 ; 

 Sars, Nory. Ech. (1861) p. 96; Duj. $ Rape, Echin. (1862) 



