So ECHINOIDEA. II. 



that its apical system is like that of P. laguncula, evidently its nearest relation. (Loven. On Pour- 

 talesia. PI. VII. Fig. 52). 



I have found two kinds of pedicellarise in P. rosea, viz. ophicephalous and tridentate. The 

 ophicephalous pedicellarise (PI. XI. Fig. 26) are rather large, with elongated, slender valves. The ter- 

 minal widening is smaller and has fewer teeth than in P. ceratopyga. The tridentate pedicellariae (only 

 one form found) have simply leafshaped valves; the eudtooth is a little prominent, the apophysis con- 

 tinues into the edges of the blade (PI. XL Fig. 15). I have noticed especially that the ophicephalous 

 pedicellariae were found on the fragment of the posterior end (— about the tridentate pedicellariae I 

 have forgot to notice that especially, so they may perhaps belong to the other fragments — ); they 

 are sufficiently characteristic for distinguishing this species from any other of the species hitherto 

 known of this genus — and, evidently, it is the species represented by the anal snout-fragment which 

 must keep the name Pourtalesia rosea, not that represented by the fragment with the apical system, 

 which is probably no Pourtalesia at all. The affinities of Pourtalesia rosea must, of course, be left 

 undecided, so long as we know almost nothing of its shape and structure of test 1 . 



Pourtalesia laguncula A. Ag. and Tanneri A. Ag. have been treated above (p. 67). 



The question whether all the species referred to the genus Pourtalesia can rightly remain to- 

 gether in this single genus has repeatedly been treated. In the Challenger -Report (p. 132) Professor 

 Agassi z comes to the result that all the species must remain in one genus, though the character of 

 the test seems to indicate two natural groups [P. ceratopyga and rosea forming one group, the rest of 

 the species another); in his last great work The Panamic Deep-Sea Echini he is inclined to think 

 that the striking differences found in the various groups of species of Pourtalesise would seem to 

 warrant the splitting up of the genus Pourtalesia into subsections. We might retain the name of the 

 genus, Pourtalesia, for the bottle-shaped types allied to P. in i ran da, such as P. Tanneri. P. laguncula, 

 P. Jeffreysi, and form a section of the genus for the elongate P. phiale and another for the stout- 

 tested P. ceratopyga and P. rosea. P. hispida may yet be found to belong to a special genus . (Op. cit. 

 p. 141). Duncan (Revision, p. 285) excludes from the genus d J . miranda and rosea on account of their 

 compact apical system and their postero-lateral interradia being separated dorsally. — Neither Agassiz 

 nor Duncan propose new generic names for the subdivisions. Pom el (Classification methodique (324) 

 p. 40) goes more radically to work. He divides the group into four genera. Pourtalesia is restricted to 

 the species miranda, hispida and (?) phiale ; a new genus, Phyalopsis, is established for P. laguncula. 

 another genus, Ceratophysa, for P. rosea and ceratopyga, and a third genus, Phyale, for P. Jeffreysi and. 

 probably, P. cariuata. 



I cannot agree with any of these proposed divisions of the genus; especially those proposed 

 by Pom el seem to me very unfortunate and quite in disaccordance with the natural relations of the 

 species. Also Duncan's exclusion of P. miranda from the genus Pourtalesia is very unfortunate, first 

 because it is the type species of the genus, and further because its apical system is, in all probability, 



1 De Meijere (Siboga-Ech. p. 169) finds the statement that the bivial ambulacra are in mutual contact only on the 

 abactinal side <so dass das Sternum hochstens von den benachbarteu Ambulacren unterbrochen sein kann: in Duncan's 

 remarks Op. cit. p. 2S1. As far as I can see this is not the meaning of Duncan, on the contrary, he probably means to say 

 that in P. rosea and miranda there is no contact on the abactinal side between the two postero-lateral interradia. In any 

 case no new information on the structure of these two species is given there by Duncan. 



