360 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [654] 
RIssoA ACULEUS Stimpson. Plate XXIV, fig. 141. (p. 306.) 
- Proc. Boston Soc. Nat. Hist., vol. iv, p. 15, 1851; Shells of New England, p. 
34; Gould, Invert., ed. ii, p. 299, fig. 568. Cingula aculeus Gould, Invert., ed. 
i, p. 266, fig. 172, 1841. Trochus striatellus Fabricius, Fauna Gronl., p. 393, (non 
Linné). (?)Rissoa saxatilis Mdller, Index Mollusca Grénl., in Kroyer’s Tids- 
skrift, vol. iv, p. 82, 1843. (?)Rissoa arctica Lovén, Ofversigt af Kongl., Vet.- 
Akad. Forhandlingar, vol. iii, p. 156, 1846. 
Long Island Sound to Greenland. New Haven, Connecticut, and vicin- 
ity, common. Watch Hill, Rhode Island; Vineyard Sound ; Stratford, 
Connecticut (Linsley); Gull Island (Smith). Common on the shores 
of Massachusetts Bay, Casco Bay, and Bay of Fundy. 
Lovén’s &. arctica was from Finmark, and, to judge from the de- 
scriptions, may not be identical with our species. Mr. Jeffreys regards 
it as a variety of R. striata of Europe. He also unites the Ameérican 
shell with &. striata, thus: ‘The variety arctica (under the specific 
name aculeus given to it by Professor Stimpson) inhabits the northern 
sea-board of the United States.” (See British Conchology, vol. iv, p. 38). 
Tt is natural to infer that a writer who does not appear to have seen 
the accurate description and figure of this species published in the 
well-known work of Dr. Gould, ten years previous to Dr. Stimpson’s 
earliest publications, cannot hae devoted much time or attention to 
the American shells, and therefore his opinions should not have too 
much weight in such cases. ; 
In reality, our shell differs widely from R. striata. It agrees more 
nearly with the English R. proxima (Alder, Forbes and Hanley), but 
apparently differs from it in the soft parts. The foot in our shell is 
broadly and slightly rounded anteriorly, with the angles only slightly 
produced, and tapers backward to a bluntly-rounded posterior end. 
The tentacles are long, slender, slightly tapering, with blunt tips. The 
eyes are situated near their bases on the dorso-lateral aspect, and are 
scarcely elevated above the general surface. The snout is rather long, 
often a little expanded at the end, and divided by a deep emargination 
into two lobes, which often, in a dorsal view, show a slight emargina- 
tion on their outer surface. No opercular cirrus was observed. This 
species belongs to the genus Onoba of H. and A. Adams. The R. 
savatilis was described by Méller as having the whorls smooth, but he 
refers to T. striatellus of Fabricius, which had spiral striations, as in our 
species. 
RISSOA EXARATA Stimpson. (p. 495.) 
Proceedings Boston Soc. Nat. Hist., vol. iv, p. 15, 1851; Shells of New England, 
p. 34, Plate 1, fig. 3, 1851; Gould, Invert., ed. ii, p. 301, fig. 571. Cingula 
arenaria Mighels and Adams, Boston Jour. Nat. Hist., vol. iv, p. 49, Plate 4, 
fig. 24, 1842 (non Montagu, sp.). Rissoa Mighelsii Stimpson, Proc. Bost. Soc. 
Nat. Hist., vol. iv, p. 15,1851; Shells of New England, p. 34; Gould, Invert., 
ed. ii, p. 301, (but not figure 570, which is probably &. yulooea). 
Stonington, Connecticut, to Gulf of Saint Lawrence. Watch Hill, Rhode 
Island, 4 to 5 fathoms, nmnongrocks and alg (white variety) ; Casco Bay, 
