INVERTEBRATE AXIMALS OF VINEYARD SOUND, ETC. 687 



aves). Greenland (Morcb). Labrador, 15 to 50 fathoms, (Packard). Fos. 

 sil in the Post-Pliocene at Montreal, rare, (Dawson) ; Brunswick, IMaine 

 (Packard). 



Possibly some of the Gulf of Saint Lawrence specimens ma^' belong- 

 to the following species. 



Cryptodon obesus Yerrill. Plate XXIX, fig. 214. (p. 509.) 



American Journ. Science, vol. iii, pp. 211, 237, Plate 7, fig. 2, 1872. • 



Shell white, irregularly and rather coarsely concentrically striated, 

 much swollen iu the middle; the transverse diameter nearly equal to 

 the length; the height considerably exceeding the length. The beaks 

 are prolonged and turned strongly to the anterior side. The lunular 

 area is rather large and sunken, somewhat flat, in some cases separated 

 by a slight ridge into an inner and an outer i)ortion. Anterior border 

 with a prominent rounded angle ; ventral margin prolonged and round- 

 ed in the middle ; posterior side with two strongly-developed flexures, 

 separated by deep grooves. Interior of shell with radiating grooves, 

 most conspicuous toward the ventral edge. 



Length of the largest specimen, 15™™; height, 18™™; thickness, 13™™. 

 The smaller specimens have about the same proportions. 



Six single valves, some of them quite fresh, were obtained off' Ro- 

 man's Land at different localities. They were all right valves, and the 

 smallest was 12.5™™ of an inch in height. The specimen from Labrador 

 agrees nearly in form and structure, and is only 5.75™™ in height and 

 5™™ in length. 



This species appears to be more nearly related to C. flexuosus of Eu- 

 rope than to C. Gouldii. The European species is nearly intermediate 

 between the two American shells in form; but judging from the speci- 

 mens that I have had opportunities to examine, the three forms ought 

 to be kept distinct. C. Gouldii is a thinner and more delicate shell, 

 more rounded, relatively much longer, and is seldom more than 6™™ to 

 7™™ in breadth. 



Block Island to Labrador. East of Block Island, in 29 fathoms, fine 

 sandy mud ; off Gay Head, 19 fathoms, mud; Casco Bay, 60 fathoms, 

 mud. Labrador (Packard). East of Saint George's Bank, 430 fath- 

 oms (S. I. Smith). 



Turtonia minuta Stimpson. 



Sbells of New England, p. 16, 1851 {non Alder, Forbes and Hanley, etc.); Gould, 

 Invert., ed. ii, p. 85, fig. 395. Venus minuta Fabricins, Fauna Gronlandica, p. 

 412, 1780. Turtonia nitida Verrill, Anier. Journ. of Sci. vol. iii, p. 286, Plate 7, 

 figs. 4, 4a, 1872. 



Massachusetts Bay to Greenland. Common under stones and in rocky 

 pools at low-water, in Massachusetts Bay and Casco Bay. Although 

 this species has not yet been found south of Cape Cod, so far as I am 

 aware, it Avill probably be found hereafter on the more exposed rocky 

 shores, as at Point Judith, Watch Hill, or on some of the outer islands. 



