MAZATLAN UNIVALVES 361 



417. HYDEOBIA TJLV.E, Penn. 



Turbo ulra, VPenn. Br. Zool. vol. iv. p. 132. Mont. Test. Brit. 



vol. ii. p. 318. Forbes $ Hani. Br. Moll. vol. iii. p. 141. 

 Paludinella stagnalis, (Linn.) Midd. Sib. Seise p. 129. ? = Helix 

 stagnalis (prima) Linn. Syst.Nat. no. 1248 : Hani. Ips. .Linn. 

 Conch, p. 380. 

 Hydrobia ulva?, H. $ A. Ad. Gen. i. pi. 35, f. 10, 10a, 6, c. 



As the Mazatlan shells, after careful microscopic examin- 

 ation, do not offer the slightest specific difference from the 

 British specimens, it did not seem allowable, merely for geo- 

 graphical reasons, to impose upon them a new name. Whether 

 it be the first H. stagnalis of Linn, as Middendorf supposes, is 

 a matter of doubt ; v. Hani. loc. cit. The well known name 

 of the English writers is therefore chosen ; and for the syn- 

 onyms, the Br. Moll, and Midd. Sib. Reise may be consulted. 

 The Mazatlan specimens were small, measuring long. '1, 

 lot. '058. 



Halt. European seas, in brackish water, passim. Caspian 

 Sea, Eichwald. Massachusetts and New York, teste Mid- 

 den dorff. South Coast of Okotsk Sea, on Algse, Midden- 

 dorff. Mazatlan ; 4 sp. in shell washings ; L'pool Col. 

 Tablet 1714 contains the smallest and the largest specimens. 



418. ? HYDKOBIA , sp. ind. 



Tablet 1715 contains a shell resembling H. ulvse, but with 

 the apex more prominent, the whirls more swollen, and a spiral 

 raised band running round a fairly developed umbilicus. It 

 has four whirls, and measures long. '036, long. spir. '016, 

 lat. '028, die. 50. 



Hob. Mazatlan ; 1 sp. off Chama ; Upool Col, 



FAMILY JEFFKEYSIAD.E. 



GENUS JEFFBEYSIA, Alder. 



Forbes fy Hani. Br. Moll. vol. iii. p. 151, 1850 : An. # Mag. 



Nat. Hist. 1851, vol. vii. pp. 193, 460. Woodw. Man. i. 137. 



Pliil. Handb. Conch, p. 172. 

 Rissoella, Gray (sine diagn.) Proc. Zool. Soc. 1847, p. 159, 



no. 286 -.Fig. Moll. An. 1850, p. SQ.Phil. Handb. Conch. 



p. 195. H. fy A. Ad. Gen. vol. i. p. 325. 

 Oct. 1856. hh 



