l68 ECHINOIDEA. II. 



Confluent posterior petals are found in Brissopsis liizonica, atlantica, elongata, Oldhami and Toxobrissus 



pacificus. 

 Divergent — — - — - — lyrifera, alta, columbaris and n. sp.^ 



5 ambnlacral piates are included in the subanal fasciole in Brissopsis luzonica, Oldhami, elongata, ii. sp. 



and T. pacificus. 

 4 — — - — -- — — - — lyrifera, alta, columbaris and at- 



lantica. 

 The first ambnlacral plate reaching within the snbanal fasciole the yth : Brissopsis elongata, n. sp. and 



T. pacificns. 



— — — — — — -— — - 6th; — lyrifera, alta, atlan- 



tica, lusonica. Oldhami, columbaris. 

 The labrnm ends off the ist adjoining ambulacral piates: Br. lyrifera, alta, atlantica. luzonica, Oldhami, 



columbaris and >i. sp. 



— — — - - 2nd — — — : - elongata and T. pacificits. 

 Globiferons pedicellariæ with the valves euding in two long hooks: Br. lyrifera and luzonica. 



— — — several short teeth surronnding the terminal opening: Br.alta. 



— — of two kinds, one with long and slender valves, ending in two long hooks, 



the other with short valves with several teeth ronnd the terminal 

 opening: Br. atlantica, columbaris (?only the slender form known), elon- 

 gata (? only the slender form known). 



— — unknown : T. pacificus, Br. Oldhami and ;/. sp. 



From this summary it is evident that none of the characters give the same grouping of the 

 species; there is such a mingling of all the characters that it seems quite hopeless to distiuguish 

 different genera among them. If different genera be maintained, they can only be characterised by 

 one of the characters named above. In that case it would perhaps be the most natural thing to take 

 the confluent ambulacra as the distinguishing character; but tlien the name Klei)iia Qiay would have 

 the priority and would have to be revived instead of Toxobrissus — the more so as the name Toxo- 

 brissus can in no case become more than a synonym of Brissopsis. as Lambert informs me in a 

 letter. I, for my part, find it preferable to keep all the recent species in one genus, Brissopsis, instead 

 of dividing them in a ratlier artificial way into two (or more) genera. 



' The species mentioned above p. 163. The Brissopsis circcsemi/a described b}- Agassiz and Clark in their 

 recently pubUshed <,Preliminar\- Report on the Echini collected, in 1902, among- the Hawaiiau Islands« iBuU. Mus. Comp. 

 Zool. L. 1907. p. 2571 has confluent petals hke those of lusonica and onl}- three ambulacral piates included by the subanal 

 fasciole. The numero of the first plate reaching within the fasciole is uuknown. The labrum is only stated to be nearl)' 

 straight; the pedicellariæ are unknown. 



