Mr. J. G. Jeffreys on British Mollusca. 46 



Skve snnd, as well as characteristic examples oi Peneroplis j)la7iatus, 

 a Mediterranean ForaniinitVr, which Mr. Barlee hail previously found 

 in the same locality. Its nearest ally, as I remarked in my pajjcr ou 

 Piedinontesc Testacea (Annals, vol. xvii. p. 18.'}), is li. vitrea. 

 Under the microscope are discernihlc some faint hut regular trans- 

 verse striae, which R. vitrea and prohably every other ai)i)arently 

 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 jiointed out to me 

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

 scope, aj)pear punctured like the toj) of a thimble. 



K. soluta, iii. 1^51. Shetland and Skye sand. 



Jeffreysia diajjhana, iii. l.")2. Barmouth; Skye sand. 



J. globularis, iv. 208. Adult specimens from Skye sand have 

 four whorls, and exhibit, under an ordinary magnlfyiuf!; power, coarse 

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

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

 dant in Skye at the roots of sea-weed. 



Skenea planorbis, iii. 15(i; var. hyalina. Skye sand. 



S. nitidissima, iii. l.')8. Tenby and Gower Coast, South "Wales 

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



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



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



Caecum trachea, iii. 1/8. Barmouth. 



C. glabrnm, iii. 181. Barmouth; Skye sand. 



Scalaria communis, iii. 20G. Barmouth. 



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. 



Odostomia acuta, var. alba, iii. 2G9. 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. pJicata 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. ]\Iy specimen from the last-named locality has all the charac- 

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

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

 form. 



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



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

 motis flexuosis leviter notata ; anfractibus 5, convcxiusculis, prime 

 subheterostroplio, ultimo reliquos superante ; sutura profunda ; 

 apertura ovali, versus basin subeffusa, tertiam spiroe i)artem 

 sequaute ; columella arcuata, dente exiguo, vix conspicuo, munita ; 



