Mr. J. G. Jeffreys on British Mollusca, 45 



Skye sand, as well as characteristic examples of Peneroplis planatus, 

 a Mediterranean Foraminifer, which Mr. Bhrlee had previously found 

 in the same locality. Its nearest ally, as I remarked in my paper on 

 Piedmontese Testacea (Annals, vol. xvii. p. 183), is R. vitrea. 

 Under the microscope are discernible some faint but regular trans- 

 verse strise, which R. vitrea and probably every other apparently 

 smooth species of Rissoa also exhibit with the same optical aid. The 

 contour, substance, and colour, however, sufficiently distinguish this 

 from any other species of Rissoa. Mr. Alder has pointed out to me 

 that the upper whorls of this species, when examined under a micro- 

 scope, appear punctured like the top of a thimble. 



R. soluta, iii. 131. Shetland and Skye sand. 

 ;; Jeffreysia diaphana, iii. 152. Barmouth; Skye sand. 

 Jt'J. globularis, iv. 268. Adult specimens from Skye sand have 

 four whorls, and exhibit, under an ordinary magnifying power, coarse 

 spiral strise. The size is half as large again as that given by Forbes 

 and Hanley. Operculum as in /. opalina. The fry are most abun- 

 dant in Skye at the roots of sea- weed. 

 ; ' Skenea planorbis, iii. 156'; var. hyalina. Skye sand. 



' S. nitidissima, iii. 158. Tenby and Gower Coast, South Wales 

 (omitted in Brit. Moll.). Skye sand. 



Id. var. hyalina. Skye sand ; very rare. 



S. rota, iii. 160. Tenby (omitted in Brit. Moll.) ; Skye sand. 

 . I Caecum trachea, iii. 178. Barmouth. 

 ojliC. glabrum, iii. 181. Barmouth; Skye sand, 

 r.ir Scalaria communis, iii. 206. Barmouth. 

 d>. S. clathratula, iii. 209. Barmouth ; Shetland sand. 

 ' Aclis ascaris, iii. 219. Arran Isle, Galway (Barlee) ; Barmouth, 



A. supranitida, iii. 221. Barmouth. 



Eulima bilineata, iii. 239. Skye sand. 



Chemnitzia? (Aclis) unica, iii. 222. Barmouth. 



Odostbmia acuta, var. alba, iii. 269. Cork Harbour (Wright) ; 

 Shetland sand. 



O. plicata, iii. 271 ; var. spira breviore, anfractibusque versus 

 basem angulatioribus ; Skye sand. This form is almost intermediate 

 between O. plicata and unidentata ; and it must be admitted that 

 many of the species are subject to considerable variation. 



O. dubia, iii. 276. Barmouth; Shetland sand. 



O. cylindrica, iii. 287. Groomsport, Belfast Bay {Waller) ; Skye 

 sand. My specimen from the last-named locality has all the charac- 

 ters of this species, except in being a trifle broader, and possessing a 

 small, but distinct, umbilical crevice, which is wanting in the typical 

 form. 



0. minima, n. s. PI. II. fig. 3. 



Testa oblongo-conica, hyalina, nitida, strigibus longitudinalibus re- 



motis flexuosis leviter notata ; anfractibus 5, convexiusculis, primo 



subheterostropho, ultimo reliquos superante ; sutura profunda ; 



' ^ apertura ovali, versus basin subefFusa, tertiam spirse partem 



^ii «equante j columella arcuata, dente exiguo, vix conspicuo, munita ; 



