468 Prof. P. M. Duncan mid Mr. W. P. Sladen on 



In young individuals the spinelets of the disk are propor- 

 tionally long, five or six times their own diameter, and pre- 

 sent all the appearances of ordinary embryonic spines. During 

 the process of growth, however, increase is made in thickness 

 only, so that when maturity is attained, and the spinelets, along 

 with the disk, are invested with the semitransparent leathery 

 membrane of the body, the appearance is more that of short 

 stumpy prominences than of actual spines — a deception which 

 at. first sight gives a totally different character to the 

 Ophiurans. 



Astrophyton arcticum (Leach), ^c?e Smith. 



Gorgmioeephalus arcticus, Leach, 1819, Append. Sir J. Ross's Voyage. 

 Astro-pliyton arcticum^ Smith, MS. 



This Astrophyton was dredged off West Greenland by Mr. 

 A. C. Horner, who accompanied vSir Allan Young in the 

 * Pandora,' at a depth of 600 fms. in Smith's Sound, lat. 

 78° 19' N., long. 74° 30' W. The present writers have not 

 seen this specimen, and are indebted for the information to 

 Mr. Edgar A. Smith, F.Z.S., of the British Museum, by whom 

 it has been determined and referred to Leach's species. This 

 is particularly interesting, as the original Gorgonoceplialiis 

 arcticus, Leach, was obtained by Sir John Ross in Baffin's 

 Bay, lat. 73° 37' N., long. 77° 25' W., at a depth of 800 fms. 

 This was one of the earliest instances of a living organism 

 being dredged from so great a depth. 



Crinoidea. 

 Antedon Eschrichiii (Miiller) and Antedon celtica (Barrett). 



Coll. Feilden : Discovery Bay, 25 fms., bottom hard. 



The Comatuke were handed over to Dr. Carpenter for de- 

 termination ; and he has kindly informed us of the occurrence 

 of the above-named species. 



Conclusions. 



It is clearly manifest that extreme caution should be 

 exercised in drawing conclusions as to the general character 

 of a fauna, on the basis of such scanty material as it is pos- 

 sible for a single expedition to furnish ; and the authors feel 

 that the great hesitation which they have in expressing defi- 

 nite opinion is fully warranted by the fact that considerable 

 additions have recently been made to the Echinifauna of 

 Northern -European waters, the details of which have not yet 

 been published ; and these investigations may, in all proba- 

 bility, have the result of going far towards rendering present 



