ECHINOIDKA. I. 



Echinoidea p. 115) is incorrect (see below). Agassiz (Challenger-Echinoidea p. 213) states that it is 

 also found in the Mediterranean, off Tristan d'Acnnha and Papua (more exactly: the Admiralty 

 Islands), and these statements are adopted by Hoyle and Bell. I cannot dispute the occurrence in 

 the Mediterranean, as I have not seen the specimens upon which the statement rests; on the other 

 hand I must maintain that the other statements are incorrect, as I have examined the specimens from 

 < Challengers that Agassiz has determined as Ech. elegans (Chall. Ech. p. 115). The specimen from 

 st. 46 (south of Nova Scotia, 1350 fathoms) is a large, fine specimen of Ech. Alexandri. Those from 

 Tristan d'Acunha are likewise a large, fine form, very similar to Ech. Alexandri (the more long-spined 

 forms). Its narrow tridentate pedicellariae , however, show that it cannot be this species; presumably 

 it is a new species, which seems to be most closely allied to Ech. lucidus Doderl. The specimens from 

 st. 219 (the Admiralty Islands), on the other hand, are something widely different from Ech. elegans. 

 There is an unpaired lateral tooth on the globiferous pedicellariae, and according to my observations 

 by the short examination during my stay at British Museum I feel inclined to think that it is nearly 

 related to Arbacina forbestana; at all events it is a sure fact that it has nothing to do with Ech. 

 elegans, and upon the whole does not belong to the family Echinid<z. 



Thus a great uncertainty is seen to have been prevailing with regard to the interpretation of 

 this species. The description of Ech. elegans given by Agassiz in Rev. of Ech., does not agree 

 with this species, but with Ech. nor-vegicus, and the figure given (PI. VII. a. Fig. 4) seems also to be 

 Ech. norvegicus\ it is not, however, to be seen with certainty, as the specimen has been less well 

 preserved. -- In conformity to this wrong interpretation of Ech. elegans Agassiz seems to have esta- 

 blished a new species, Ech. Wallisi, for the real Ech. elegans. As mentioned above (p. 100) I have 

 received a specimen from U. S. National Museum, determined as Ech. Wallisi, which is no doubt a 

 large specimen of Ech. elegans, only a little more short-spined than is usually the case. But I think 

 it must be regarded as a little doubtful, whether it is really Ech. Wallisi. It does not agree very well 

 with the description of this species, especially must be pointed out that its pores are trigeminate as 

 usual in Echinus. But, according to Agassiz Ech. Wallisi is distinguished by the arrangement of 

 the pairs of pores in sets of two (Blake-Echini p. 39). It is impossible for me to decide how the 

 fact really is, but to judge by this specimen it is a sure fact that Ech. elegans is found off North 

 America, and that Ech. Wallisi is either synonymous with it - - but then its pores are trigeminate 

 and not in sets of two - - or that it is a separate species with the pores in sets of two, but then it 

 is no Echinus. At all events it is to be regretted that Agassiz has given a so deficient description 

 of a new species, and, moreover, has not given any figure of it at all. 



Judging from the material of Ech. elegans we have from the Ingolf-Expedition, it is a very 

 varying form. If we compare the test of a subconical and a higher form, we might be led to sup- 

 pose them to be two separate species. But transitional forms are found, and especially no difference 

 seems to be found in the pedicellariae. For the present I must regard them all as one species, but 

 the possibility is not excluded that by means of a larger material we may be able to distinguish dif- 

 ferent forms. It is, however, I think, more likely that it will show a richness in forms similar to that 

 of Echinus Alexandri, in which case the Challenger-specimens from Tristan d'Acunha will perhaps 

 nevertheless have to be referred to Ech. elegans. 



IQ 



The Ingolf-Expedition. IV. i. 



