Bd. VI: 4) THE ECHINOIDEA. 45 



given b)- both Lamakck and Blainville, that it was not the species called thus 

 by Agassiz. The figures given by VALENCIENNES equally speak decidedly against 

 the identity with Agassiz' species (whether they really represent Lamakck's species 

 or another species {uiagellaiiictis.-)). The result is then unquestionably that the spe- 

 cies described and figured by AOASSIZ cannot righth' keep the name iiiargaritaccus; 

 I propose to name it Stcrecliinus Agassi sit. 



In »Stellérides, Ophiures et Echinides» de l'Expédit. antarctique Française» KoEH- 

 LER, after reproaching me for the confusion which I have raised in this case in my 

 »Ingolf» Echinoidea, describes as -nEchitms niargaritacens-» a species which is quite 

 different from both the ntiargaritaceusi> of AOASSIZ and from the species which I 

 had taken to be this species (viz. Stcrech. diadema). It is Sterecliinus Neumayeri, 

 as is stated by Prof. KOEIILER in his later work on the »Astéries, Ophiures et Echi- 

 nides de l'Expédition antarct. nationale Ecossaise» p. 616. (I have myself had occa- 

 sion to examine a pair of these specimens, kindly sent to me from Prof. Koehlek.) 

 At length all these species, ■uniargaritaceiis^, diadana, antarcticns, Neumayeri and 

 /lorridus, were diagnosed and redescribed by DÖDERLEIN (Op. cit.), to whom thus 

 belongs the merit of having first cleared up this rather difficult case. 



The reasons for the erroneous determinations by myself and Prof. KoEHLER are, 

 partly the scarcity of the material at disposal, partly the insufficient descriptions 

 given in the »Revision of Echini» and in the »Hassler» Echini; scarcely other cha- 

 racters are pointed out than such as distinguish the whole genus Stercchiitus. The 

 only figure given, Pi. II. b of the »Hassler» Echini, is likewise quite insufficient for 

 distinguishing this species from diadema and Xeumayeri; in fact, KoEHLEK takes 

 this figure as a proof of his species {Neumayeri) being the true ^margaritaceus-», as 

 I have taken it as a proof that my species (diadema) was that species. DöDERLElN 

 finds in this figure that all the ocular plates are excluded from the anal area (he 

 wrongly writes »Apicalfeld», p. 218). I wonder how it is possible to see that on 

 this figure; I am quite unable to distinguish more than three of the ocular plates, 

 and these probably are excluded from the periproct, as also KOEHLER remarks 

 (Expéd. antarct. Franc, p. 33). — (On the other hand, I find this figure, as also 

 PI. III. figs. 4 and 5, to be inverted; this is indicated by the fact that the anal 

 opening is here represented as lying to the left side, while, as is well known, 

 it really lies to the right (off Ocular I), the animal being orientated after Lo- 

 VÉn's plan.) 



In order to acquire full certainty of the identity of the specimens in hand with 

 the species figured by AcASSlz I sent one of the specimens to Professor H. Lyman 

 Clark asking him to do me the favour to compare it directly with the specimen 

 figured in the »Hassler* Echini. He kindly informed me that he found it to be the 

 same species. I also sent one specimen to Professor DÖDERLEIN, asking him to 



