BRISSOPSIS. 



the anal and subanal fasciol.es were developed, but had not the outline they 

 assume in the adult. The general color of the tests and spines was straw- 

 colored. 



61. 



52.1 



China. 



36.3 



19.8 



17. 



19. 



18. 



(HEMIASTER.) Brissopsis. 



Brissopsis Agass., 1840, Cat. Syst. Etyp., p. 16. 

 (See Part II. p. 354.) 



17. 



14. 



Brissopsis luzonica 



! Kleinia luzonica Gray, 1851, Ann. Mag. N. H., VII. p. 133. 

 I Brissopsis luzonica A. Ag., 1872, Rev. Ech., Pt. I. p. 95. 



The mere confluence of the lateral ambulacra does not constitute, as I 

 have shown in the history of the changes of Brissopsis lyrifera, a sufficient 

 reason for separating generically the East India species from Brissopsis, as has 

 been done by Gray. It is true that this confluence commences earlier than 

 in the European species ; but it is found in the latter ; and the other struc- 

 tural features agree so well with Brissopsis, that it is impossible not to as- 

 sociate these species in the same genus. 



Test thin ; seen from above the outline is rounded anteriorly, indented 

 by the odd ambulacral groove, pointed towards the posterior extremity, 

 which is bevelled. The general outline in profile does not differ mate- 

 rially from that of Brissopsis lyrifera, the test perhaps sloping somewhat 

 more towards the anterior edge. The lateral ambulacra are confluent ; the 

 anterior arched towards the posterior end at the extremity ; the posterior, 

 arching towards the peripetalous fasciole, run parallel to the curve of 

 the ambulacra in the posterior interambulacra. and as the apical portions 

 of the posterior poriferous zone of the posterior lateral ambulacra are wholly 

 obliterated, the posterior extremity of the peripetalous plastron is pointed, 

 compared with its outline in Brissopsis lyrifera. The subanal plastron is 

 divided by a vertical branch in two parts (this is rudimentary, or does not 

 exist in B. lyrifera) ; the anal branch of the fasciole is prominent ; the anal 

 system is smaller in proportion to the size of the test than in B. lyrifera. 

 The anterior groove is somewhat deeper. The general mode of arrangement 



