Mr. Jeffreys on British Mallusca. 191 



of " burrowing," or excavating the stones and shells in which it is 

 often found. Sometimes adult specimens have their shells strangu- 

 lated, and more or less distorted, so as completely to tit the cavities 

 in which they are enclosed ; and I believe this mollusk, like Kellia 

 suborbicularis, only uses the excavations which had heen previously 

 made by Annelids. I suspect the same to be the case with Cliona 

 perforans, and that this curious Sponge only occupies deserted gal- 

 leries. 



Mya truncata, i. 1G3. A young specimen was taken alive in 80 

 fathoms water, by dredging off the coast of Antrim, at a distance of 

 about ten miles from the shore. This species, as is well known, is 

 usually found between tide-marks. 



Poromya granulata, i. 204. A comparison of our shell with a 

 specimen of the Embla Koreni of Love'n from Upper Norway induces 

 me to confirm the surmise made by the authors of the 'British 

 Mollusca,' that they are one and the same species. Nyst's specific 

 name, however, has precedence in date. 



Thracia convexa, i. 229. A young specimen was taken by Mr. 

 Barlee in Zetland last year. 



T. distorta, i. 231. I believe this is only an abnormal form of T. 

 villosiuscula, and that they constitute but one species. The former 

 name has, of course, the priority, although it is not so generally 

 appropriate as the other. The first lines of growth are evidently the 

 same in each ; and it is only after the habitat is changed that a 

 marked difference appears. The Anatina truncata of Tarton may 

 be regarded as an intermediate form. An analogous difference, 

 occasioned by the habitat being free or enclosed, occurs in Tapes 

 jmltastra and its variety perforans, which was formerly considered 

 a distinct species. 



Lyonsia Norvegica, i. 214. St. Martin's Bay, Guernsey (J.G.J.); 

 St. Catherine's Bay, Jersey (Rev. A. M. Norman). 



Solecurtus candidus, i. 263. In dredged sand from Belfast Bay. 



Psammobia costulata, i. 2/9. With the last. 



Syndosmya tenuis, i. 323. Gronville and St. Catherine's Bays, 

 Jersey (Rev. A. M. Noi'tnan). 



Mactra elliptica, i. 356. I am much inclined to doubt, this being 

 anything more than a deep-water variety of M. subtruncata, having 

 intermediate specimens from Guernsey and Ardrossan, in the last of 

 which the transverse sulci only appear in the later period of growth. 



Tapes pullastra, i. 382. Pl large, but w r orn, single valve, which 

 belongs to the form named by me Venus plagia (described in the 

 1 Annals of Natural History,' ser. 2. vol. xix. p. 313), has been found 

 by Mr. Hyndman at Larne in Belfast Bay, and was obligingly pre- 

 sented by him to me. It measures 2f inches in length, and If 

 in breadth. The peculiar obliquity of its shape and greater breadth, 

 as well as the acute angle in which the anterior extremity terminates, 

 incline me to retain my former opinion that it is not a variety of 

 T. pullastra. In some respects it resembles T. virginea. 



T. aurea, i. 392. Southend, Essex. 



Circe minima, i. 446, var. latior et complanata. Belfast Bay. 



