l(y ECHINOIDEA. II. 



recognize tlic \ahie of affinities not based on the pedicelkuiæ, siuce, of course, oiih tlic accordance 

 in the stinictural characters of the test could indnce nie to accept sncli genera. To be snre, the Stereo- 

 cidaru canalicuLata is not a \er>' typical species of that genns, but the pedicellariæ are of the strnc- 

 tnre pecnliar to that genns, and I did not find snfficient charaters in the strnctnre of the test for 

 foiinding a separate genus on it. Novv, Professor Agassiz has established the genus Cnitrocidnrix 

 for this species and the species Goniocidaris Dodcrleini \. h.^., the only character of the genns being 

 the broad bare space in the ambulacral and interambnlacral areas. This character is certainly a ver\ 

 insnfficient one for fonnding a genns on it, the more so as it is rather \ariable in canalindata. Pro- 

 fessor Doderlein qnite agrees with nie that the species canaliculata has to be referred to Stcreo- 

 cidaris^; he rejects the genus Cnifrocidaris, and I think, Hkewise, that this genus cannot be niaintained 

 as nnderstood In Professor Agassiz. Perhaps it can l)e niaintained for the species C. Dodcrlrmi, 

 which had to be left incertæ sedis b\' Professor Doderlein, in spite of the carefnl description of the 

 test given b\ Professor Agassiz ni tlie Pananiic Ueep-Sea Echini. 



Professor Agassiz fnrtlier finds it inipossible to concei\e the ground for my separating Pcna- 

 ciduris irlegans as another genus, Histocidaris, from Porocidaris purp-tirafa, imless it be that the cha- 

 racters of a single valve of a small globiferons pedicellaria, which he (I) figure(s) as perhaps belonging 

 to that species 2, is snfficiently characteristic for such a generic separation« (p. 24). It seenis to me to 

 be very easily seen from m\- remarks on Porocidaris (p. 21 — 22) and the diagnoses of the genera Histo- 

 cidaris and Porocidaris (p. 30), that I regard the differences in the tridentate pedicellariæ as the main 

 character: two-valved in Porocidaris. ihree-valved m I/islocidaris; the depressions in the scrobicular areas 

 and the long neck of the radioles are also pointed out as characteristic of Porocidaris |p. 21) — un- 

 fortnnateh , the tvvo latter characters have not been mentioned in the diagnosis. I do not see that 

 Professor Agassiz has in the least weakened these gronnds for åisthigmshing J-/isiocidaris hon\ l'or«- 

 cidaris; Professor Doderlein also accepts the genns ITistocidaris. though he finds that the two 

 species einander nicht allznfern stehen (p. 98). I agree that it is too mnch to say that H. elcgans \\a.s 

 no relation with P. piirpurata (p. 22), but 1 think the genus I/isfocidaris has to be niaintained. — To 

 this genus will have to be referred i Porocidaris' Cobosi h. Ag., of which I liave examined an authentic 

 .specimeii in the U. S. National Mnsetim, whereas ^Porocidaris Miller i A. Ag., which I had Hkewise 

 the opportnnit\ of examining there, is a Stereocidaris, probabh' nearly related to Stcrcocidaris japonica 

 Doderlein. As regards Porocidaris Sliarrcri it still remains nncertain, whether it is a Porocidaris or a 

 /fistocidaris ; it is true that I haxe seen the tvpe-specimen in the Museum of Comparative Zoolog\ 

 at Harvard College, bnt since Professor Agassiz thonglit it right to forbid me to make any studies 

 at the Museum, I could only see it like any ordinarx visitor. and unfortimately it was placed so higli 

 that I conld not see the pedicellariæ. From the lack of a long neck on the spines and of the de- 

 pressions in the scrobicular areas I wonld conclude that it belongs to the genns Histocidaris. What I 

 have said of the species Dorocidaris micaris. based 011 specimens wrongh' referred to Porocidaris Sliar- 

 reri, is right. I liope to be able soen to give a more detailed description of this species. On the 

 otlier hånd, I must agree that Professor Agassiz is right wlien reproaching me with inconsistencv iu 



' I shall have to treat this species aud the (|iiestioiis associated theiewith more thorout;hly in tlie Reports on the 

 Ivchiiii of the Gerniau and the Swedish .South-Polar Expeditions. 



- On p. 173 I have stated that this form of globiferous pedicellariæ does not really belon,!;; to Hisloc. e/egatts. 



