128 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Feb. 19, 



/'l. Hydrobia vlvm, Pennant. 



Turbo ulvce, Penu. Br. Zool. iv. p. 132, pi. lxxxvi. p. 120. 



Hydrobia ulvce, B, C. iv. p. 52; v. p. 208, pi. lxix. f. 1. 



'Porcupine' Exp. 1869: St. Donegal B. (type and vars. barleei 

 and octond), 19 (var. barleei), 58 (same variety). 1870 : Med. 50 

 (var. subumbilicata). 



Distribution. Everywhere between tidemarks and in brackish 

 water throughout the eastern portion of the North Atlantic, from 

 Finmark and Novaia Zemblia, southwards to the Mediterranean and 

 Adriatic; California (P. Carpenter)? A chance specimen of the 

 variety barleei was dredged in the Bav of Biscay during the 

 « Travailleur ' Expedition of 1880 at the depth of 1062 fathoms ! 



Fossil. Pliocene and Post-tertiary : Scandinavia, Great Britain 

 and Ireland (including the Coralline, Red, and Mammalian Crags), 

 Leghorn, Southern Italy, and Rhodes. 



This abundant and widely distributed little shell has long served 

 as a manufactory of nearly countless species; and even undistin- 

 guishable and useless genera, such as Peringia and Peringiella, 

 have been invented to show the ingenuity of ambitious concho- 

 logists. Assiminea gallica of the late Dr. Paladilhe is another 

 synonym, as I have ascertained from the inspection of typical 

 specimens which that author kindly sent me. Turbo minutus of 

 Totten, which inhabits similar situations on the western coasts of 

 North America, and which I found plentifully on the seaboard of 

 Canada and New England, appears to be a different species. See 

 also ' British Conchology ' for synonyms and varieties. 



2. Hydrobia compacta l , Jeffreys. (Plate IX. fig. 9.) 



Shell conical, thick, semitransparent, and glossy : sculpture 

 none, except in the periphery being obtusely angular : colour yel- 

 lowish : spire rather short, bluntly pointed : whorls 6, flattened, 

 gradually increasing in size ; the last occupies about two thirds 

 of the spire when viewed in a supine position : suture slight but 

 distinct : mouth oval, contracted above and angular below : outer lip 

 somewhat thickened : inner lip also thickened, and reflected on the 

 pillar : peristome continuous : base imperforate. L. 0"175. B. - l. 



'Porcupine' Exp. 1870: Atl. St. Tangier B. Several dead 

 specimens. 



Differs from H. ulvce in its shape, which is that of a short cone, 

 in the periphery being angular or keeled at all stages of growth, and 

 in the base being imperforate. I caunot identify the present species 

 with any of those which were described and figured by Paladilhe 

 in his ' Nouvelles Hiscellanees Malacologiques.' Much confusion 

 seems to have been caused by him and other continental writers, 

 not only in making so many worthless genera of this family (Lit- 

 torinidce), but in referring species of Hydrobia to Assiminea, which 

 belongs to the Pulmonobranchiata. For instance, in describing his 

 Assiminea obeliscus (which is apparently one of the numerous 



1 Compact. 



