188 CATALOGUE OF ADDITIONS TO, AND ALTERATIONS 



tliey must be C. claviis, varieties Smittii and borealis. Conse- 

 quently the Cornish, form is G. clavus, var. Smittii. 



In Shetland, when with Mr. Jeffreys dredging in 1 864, I 

 made a series of drawings from living specimens of the 

 Garyophyllia clavus, var. borealis, got there, as I well knew the 

 animals of the Cornish species. I could find no difierence in the 

 two varieties, and took great pains to see whether a difference 

 could be made out, and became fully convinced that none could 

 be. The sketches I lent Professor Duncan, and from these he 

 had plates made to illustrate his paper on the subject, and fully 

 concurred in the conclusion I had come to, that the animals were 

 the same, and that the difference in the shape of the Coralline 

 arose from the Cornish ones having stones and shells to form 

 upon, with plenty of room for a wide foundation. The Shetland 

 ones, on the contrary, in the abyssal depths had only the Dentalium 

 like small cases of the Ditrupa to build upon, and thus its top- 

 like shape and small base. 



Occasionally, Cornish ones are found with very narrow bases, 

 and of peg-top shape, from being built upon small things. In 

 the Shetland seas — rarely however — they fix on a piece of shell 

 or stone and have a wider base, thus showing that the difference 

 in shape arises from accidental circumstances, and not from 

 specific differences. Generally, the Cornish specimens, if mingled 

 with others from Shetland, could be detected at once by their 

 bearing specimens of the pretty Pyrgoma Anglica perched on 

 the outer edges of the plates ; the Shetland ones also have 

 their distinguishing mark, from being perched on the tube cases 

 of Ditrupa arietina, such not being found in Cornwall, and thus 

 it may mostly be detected by the company it keeps. 



In one of the broken specimens of CaryohpyUia clavus, var. 

 horealis, I observed Cnidi — Aconita or thread-bearing cells — 

 such had not before been noticed in this Coral. 



Genus, Sphenotrochus. — M. Edw. & Haime. 



1 — Sphenotrochus Wrightii. — Gosse, plate x, fig. 3, p. 326. 



This pretty coral I got in sand procured from Lantivet Bay, 

 — see Journal of Eoyal Institution of Cornwall, No. 10, 1869, 

 p. 11 7 ; — it is a small species and has a wide range. I also found 

 four specimens in sand dredged by Dr. J. Grwyn Jeffreys off 

 Shetland, in from 80 to 100 fathoms, 1864. (C.W.P.) 



