BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 13. AFD. lY. N:0 5. 101 



lection preserved in the Museum of the University of Erlan- 

 gen, the one of whicli sixteen years ago Troschel gave a 

 very accurate description as Echinocidaris pustulosa Leske, 

 now is before me, Tab. 3, jig. 6, thanks to the kind liberalitv 

 of Professor Selenka. It has been supposed to be the original 

 of Klein's fig. 6', but seems to me to accord as well if not 

 better with his fig. A. Its upper side is in a good state, but 

 the basis much broken. It is somewhat flattened, the heio-ht 

 being 18 mm., or 0,43 of the diameter of 42 mm., which is 

 lower than in any of the three larger Linnean types, but with 

 this difference it has all the characters of the A. Lixula L. The 

 tubercles, very slightly larger than those of the specimen a, 

 are somewhat smaller than those of the specimen b, their in- 

 creasing rarity on the upper parts is as striking, and the ad- 

 ventitious tubercles are very nearly as in Klein's figure A; 

 tlie ambulacral areola is linear but distinct, and beset with 

 epistromal nodules as in the type specimens, and tlie epistroma 

 of the interradia is quite as strongly developed. The general 

 coloiir is a little darker than in the Linnean specimen 6, the 

 mamelons greenish, the zones chesnut. In short, the difFerences 

 observable between the two types are individual; in each 

 they are specific with the regard to the other known members 

 of the genus. 



Leske's description of his Cidaris pustulosa, which, how- 

 ever, is made, as usual, not from the originals of Klein but 

 from specimens in the collections of Trier and Linck, agrees 

 very well with the types of the A. Lix;xla L. It alludcs, to 

 the epistroma and the prominent nib of the gill-supports. 



Troschel expressly says that he had seen no other spe- 

 cimen than the Kleinian one of the Erlangeu Museum, and 



O' 



gives the coast of Brazil as its habitat. But neither Klein 

 nor his commentator Leske indicate the habitat of any of the 

 species they describe, and Troschel canuot but have borrowed 

 »BraziL> from the :>Cataloo;ue Kaisonné» of Agassiz and Desor, 

 where it occurs for their Echinocidaris pustulosa. This, how- 

 ever, is not the species described under that name by Leske, 

 while, on the other hand, the only Arbacia known to in- 

 habitat the Brazilian coast is not the A. Lixula of Linn^us. 

 Thus we have to o;o elsewhere to find the source from Avhich 

 were derived the types in tlie Queen's Cabinet. Out of the 

 llrst set, in this collection, of fourteen species, one, the E. 



