l56 ECHINOIDEA. II. 



(or elongaia),^ the confusion of this species with lyrifera having caused the erroneous statement of the 

 development of the petals. — It is also a curious faet that in the -Blake -Ech. p. 70 Agassiz speaks 

 of the confluent anibnlacra as an « embryologi cal character , in direct opposition to the above citations, 

 where this character is said to be developed with age. 



The subanal fasciole is also said (Rev. of Ech. loc. cit.) to be snbject to very great changes, 

 dne to different stages of growth; in the Blake -Echinoidea it is even stated to have disappeared 

 completelv in some specimens, viz. in the globular specimens from off Missisippi. That none of these 

 globular specimens are reall\' Br. lyrifera, I think beyond donbt; the_\- will probably tnrn out to be 

 partlv Br. alta and partly, viz. those without a subanal fasciole, Pcriaster limicola. (To be sure, I have 

 not myself seen any specimens of Periaster limicola identified as i.Brissopsis lyri/era», but I have seen 

 specimens of Brissopsis < lyriferay> (alta) identified as Periaster limicola (comp. above p. 159), so it may 

 not seem very hazardous to suggest that the reverse case may also be found). Until by a renewed 

 examination of these globular specimens without a subanal fasciole it is shown definitely to which 

 species they belong, I must doubt that they belong to the genus Brissopsis. So far as my experience 

 goes — and I have examined a considerable number of specimens, especially of the species lyrifera 

 and luzonica — the subanal fasciole is very constant in tliis genus, as upon the whole this fasciole is 

 one of the most constant features in the Amphisternous Spatangoids. That it may, however, sometimes 

 really disappear I have shown above |p. 129) for Spatangus Raschi. — On the other hånd there is really 

 considerable variation in the anal branch, the small fasciole running from the subanal fasciole along 

 the sides of the anal area straight towards the peripetalous fasciole in the Brissopsis-s^&c\&?, , as 

 pointed out by Agassiz. But this fasciole must, of course, not be confounded with the subanal fasciole. 

 In the true Br. lyrifera the anal branch is very seldom developed; only in a single specimen («Ingolf» 

 St. 6) they were both distinctly developed, reaching the peripetalous fasciole; in a very few instances 

 I have found sliglit traces thereof. 



In the vPanamic Deep Sea Echini (p. 193) Professor Agassiz maintains the old genus Toxo- 

 brissiis Desor, pointing out the following characters as distinguishing it from Brissopsis : The genital 

 piates of Toxobrissus do not extend into the interambulacral areas, which they do in Brissopsis. The 

 extremities of five ambulacral piates are included in the «anal;> (viz. subanal) fasciole of Toxobrissus^ 

 whereas only four are so included in Brissopsis. The labrum of Brissopsis is shorter and more T-shaped 

 than in Toxobrissus. Further «the arrangement of the apical interambulacral piates of the odd inter- 

 ambulacrum shows at once the radical difference existing between Toxobrissus and Brissopsisv. The 

 confluence of the posterior petals is not recognised as a character of the genus Toxobrissus. 

 the West Indian specimens of '^Brissopsis lyrifera» with confluent ambulacra being expressly stated not 

 to belong to the genus Toxobrissus (p. 191. Note); on the other hånd it is said (p. 193) after pointing 

 out the characters mentioned above as distinguishing Toxobrissus and Brissopsis — «that we are 



■ Bittner (Uber Parabrissus und einige andere alttertiåre Echiniden-Gattungen. Verhandl. d. K. K. geol. Reichs- 

 anstalt. 1891. p. 137) has already suggested that these figures do not represent one and the same species — ;eine Umwaud- 

 lung von Taf. XIX. Fig. 8 durch Taf. XIX. Fig. 9 in Taf. XXI. Fig. 2 anzunehinen, diirfte sehr gewagt sein -. .\lso Pomel has 

 perhaps seen that; in any case he says (Classif. méth. p. 33): »le prétendu Brissopsis lyrifera de la Floride est probablement 

 une autre espéce vivante«, viz. of tlie genus Kleinia^ which he maintains as a separate genus. 



