TT hen Alexander Agassiz made known the resixlts obtained from the dredg- 

 ings in deep water executed in the yeai" 1868 between Cuba and the Florida Reef 

 by the late Count Louis-FRANgois de Pourtales, ') there was, among numbers of Echi- 

 noidea then for the first time brought to light, none that excited more wonder and 

 curiosity than the very singular animal described under the doubly appropriate name 

 of Pourtalesia miranda Al. Ag. Nor was the interest its stränge and abnormal aspect 

 awakened in any way lessened, when the same author, in his great work on the Echi- 

 noidea, ^) gave a description, accompanied with iigures drawn by himself, and the late 

 Sir Charles Wyville Thomson, shortly afterwards, added two new species, Pourtalesia 

 Jeffreysi and P. phiale, and at the same time threw fresh light upon several impor- 

 t^ant points in the structure of the former of these. ^) 



Alexander Agassiz had the extraordinary kindness to lend me, for inspection 

 and study, his unique specimen of Pourtalesia miranda. Such is, however. the exces- 

 sive thinness and fragility of this species, that I did not feel warranted to do more 

 than subject it to repeated, but superficial examination, coniirming the general accuracy 

 of the oi'iginal description and figures, and to speculate, during the long time it was 

 allowed to remain with me, upon the presumable morphological relations existing be- 

 tween the parts composing its skeleton and the corresponding parts in the other Echi- 

 noidea, which had then for several years been to me a subject of some study. 



In the mean time my Norwegian friends, in the course of their well-planned and 

 highly successful survey, on board the Steamer »Vöringen», of the Hydrography and 

 Biology of the North Atlantic, had the good fortune to fall in with a habitat of Pour- 

 talesia Jeffreysi, and, with a liberality I cannot too amply acknowledge, through one 

 of their stafi', D:r D. C. Danielsen of Bergen, placed at my disposal several more or 

 less uninjured specimens as well as some fragments of that species, and thus afforded 

 me the long wished for opportunity of examining, fully and at leisure, the most extra- 

 ordinary Echinoid hitherto known. 



I have also to express my deep obligations to the late Sir Wyville Thomson, 

 who most kindly came to my aid with a few specimens of Pourtalesiaj collected 



') Preliminary Report on the Echini and Starfishes dredged in deep water between Cuba and the Florida 

 Reef, by L. F. de PouiiTALiäs, Assist. U. S. Coast Survey; prepared by Alexander Agassiz. Bulletin 

 of the Museum of Comparative Zoology, Cambridge, I, N:o 9, Oct. 1869; p. 272. 



'^) Illustrated Catalogue of the Museum of Comparative Zoology at Harvard College. N:o VII. Revision 

 of the Echini by Alexander Agassiz, p. 344, Pl. XVIII. 



^) Wyville Thomson, the Depths of the Sea, p. 108, fig. 12. — On the Echinoidea of the »Porcupine» Deep- 

 sea Dredging Expeditions. Phil. Träns. Roy. Soc. London, Vol. 164, pt. 2. p. 747, pl. LXX, LXXI. 



