Mr. Jeffreys on British Mollusca. 197 



appears to bear the same relation to the typical form that the Helix 

 rupestris of Continental authors does to our H. umbilicata. 



S. striata {Valvatal striata, Phil. i. 147, t. 9. f. 3, and ii. 122). 

 Two specimens have been found by Mr. Waller at Bundoran, in the 

 North of Ireland, one of which he obhgingly presented to me. It 

 cannot be mistaken for the young of any British species of Trochus. 

 My specimen is nearly one-tenth of an inch in diameter. Although 

 Philippi provisionally assigned it to the genus Valvata because he 

 found it in a fossil state, associated with Cyrena gemellaris as well 

 as with marine shells, he subsequently thought it might with equal 

 propriety be referred to his genus Belphinula. Mr. Searles Wood 

 has, in his *Crag Mollusca' (Univ. p. 137, tab. 15. f. 7), referred to 

 Philippics species some fossil shells under the name of Adeorbis 

 striatus ; but I am not satisfied that there are sufficient generic cha- 

 racters for distinguishing Adeorbis from TrochuSy taking Adeorbis 

 subcarinatus as the type. 



Skenea? Isevis, iii. 165. Mr. Barlee has found another specimen 

 in dredged sand from the Shetland s. I do not beheve it is the Bel- 

 phinula Icevis of Philippi ; and if it proves to be distinct, I woidd 

 suggest that the specific name of nitida be given to our species. 



Euomphalus? (Omalogyra) nitidissimus (Skenea t nitidissima, iii. 

 158). On Zostera marina, between tide-marks on the shores of 

 Larne Lough, Ireland. 



E. ? (Omalogyra) rota {Skenea 1 rota, iii. 160). Serk (Mrs. 

 Collings) . 



Csecum glabrum, iii. 181. It is possible that the Serpula incur- 

 vata of Adams, instead of being the fry of this species (according to 

 Mr. Clark), may be a species of Bifrontia. I possess apparently 

 very young specimens of C. glabrum, which merely show a greater 

 curvature of form with a less diameter than the adult, and present 

 the same relative differences that exist between the Dentalium imper- 

 foratum and trachea of Montagu. 



Cerithium niveum, Je-^r. in Ann. Nat. Hist. Mr. Waller has 

 found specimens of different ages (but more or less imperfect) by 

 dredging on the north-eastern coast of Ireland. It is a true Cerithium. 



Stylifer Turtoni, iii. 226. Mr. Leckenby informs me that a fine 

 specimen (three-eighths of an inch in length !) was found a year or 

 two ago at Filey by Miss Backhouse. In a note which I have re- 

 ceived from Mr. Howard Stewart, as to this rare and interesting 

 species, he says, ** Amongst my numerous dredgings for the British 

 Echinoderms on the Plymouth coast, I have carefully looked over 

 vast numbers of sea-eggs, &c., for the Stylifer Turtoni, but have 

 never found it except on Echinus miliaris. In October or November 

 1855, I found six Sty lifers on one Echinus miliaris, but only one of 

 these was adult ; and on another specimen of E. miliaris I obtained 

 an adult specimen of the mollusk, and the ova of the same. The ova 

 were so far advanced as to be seen swimming about by means of 

 coarse cilia under the microscope with a low power, and the shells 

 were perfectly formed." Mr. Stewart has since obligingly presented 

 me with these ova, which are disposed in two clusters (probably 



