124 



Echinometra-species, as they did nol seem to present differences of greater interest, 

 so I did not revise the determination of this species. What I took for oblonga, 

 now proves to he E. Matthœi and thus my statements for oblonga are v>'rong. E. 

 oblonga differs, indeed, very markedly from the other /sY/izno/ne^ra-species in having 

 triradiate spicules in the tubefeet (PI. V. Fig. 26); bihamate spicules, however, 

 may also occur together with the triradiate ones, and transitional forms between 

 bihamate and triradiate may be found; also the tridentate pedicellariæ are cha- 

 racteristic (PI. VII. Fig. 35), whereas the globiferous pedicellariæ are like those of 

 the other species (lucunter etc.). (I have not examined the type-specimen.) This 

 species thus is quite unique among the Echinometrids, which have otherwise biha- 

 mate spicules (only in Selenechinus de Meljere they are thorny), and must perhaps 

 form a separate genus. I shall, however, not propose a name for it. The tri- 

 radiate spicules can evidently not be regarded as a primitive feature; the transi- 

 tional forms from the bihamate spicules seem to indicate that they are a further 

 development from the bihamate ones. That would also agree with the fact of this 

 species being the most elongate of all Echinometrids. 



In his paper „Echinoderms from Puget Sound" (Proc. Boston Soc. Nat. Hist. 

 XXIX. 1901. p. 331) Clakk mentions Echinometra oblonga from that locality. This 

 seems very improbable. The statement that Astropygn pulvinata and Toxopneustes 

 pileolus occur on both sides of the Pacific has been proved to be erroneous, and it 

 seems very doubtful if any littoral species does so. In any case a very close 

 examination must be made of such species, before so wide a distribution can be 

 accepted as a certain fact. 



Mrs. R. I. PococK has kindly undertaken the revision of the language in 

 the present work. I beg her to accejil my best thanks for this service. 



