NO. 1139. / 1 /: /; I'.ir.i TE i; MOLLUSCAV /: i; i: ILL A \D j;rs/i. , ;- I 



MONTACUTA OVATA Jeffreys. 



(Plan- XCII, tigs. !l. lO.i 



Ti'llimya fcrrnginosa VERRILI.. Notice of Reeent Add. to Mar. Invert., Pt. ::. 



Pro.-. 1 1. S. Xat. Mns., III. p. 100, 1880. 

 Muiilm-itta orata JEI- KUF.YS. 1'roc. Xoi'il. Soc., London, p. 698, pi. i.xi. fig. 4, 



Juno. 1881. VEKRIJ.L, Trans. Conn. Arad.. V, p. 571, 1**-!: VI, p. i'7!. ll. 



A very few specimens, at four stations, off Newport. Uhode Island, 

 and oil' Marthas Vineyard, ill 100 to 157 fathoms, 1880-81. 



MONTACUTA TUMIDULA Jeffreys. 



(Plates XCI1I, fig. 0; XCIV, figs. 1, 2.) 



Montacuta tumidula .JEFFREYS, liritisli Conchology, V, p. 177, pi. C, fig. 5, 1869. 



<;. O. SAKS, Mollusca Reg. Arctica- Norvegia-. p. 00, pi. 10. figs, is a -b, 1878. 

 VEKKII.I., Trans. Conn. Acad., VI, pp. .'5, L'79, 1884; Expl. Alli<itrxx, Report 

 I'. S. Com. Fish and Fisheries for is*;-!, p. 575. 1SS5. 



One live specimen and three valves, at three stations between X. hit. 

 40 7', W. long. 07 54', and N. lat. 3-3 49' 30", AY. long. 74 34 X 45", 

 in 843 to 1,091 fathoms, 1883-1880. 



MONTACUTA CASTA, new species. 

 (Plate XCIV, fig. 5.) 



Shell small, compressed, oblong-ovate, with the anterior end consid- 

 erably the longer and both ends about equally rounded. Beaks small, 

 scarcely rising above the margin. Surface covered with tine, regular, 

 microscopic, concentric stria' and distant, raised lines of growth. The 

 antero-dorsal margin is at first a little incurved, then slightly convex, 

 with a gradual slope; the anterior end is obtusely rounded; the ventral 

 margin is broadly and evenly rounded; the posterior end is slightly 

 produced and a little angulated below, in some specimens with the 

 dorsal margin sloping more rapidly than the anterior and slightly 

 incurved near the beaks. The hinge-margin is thin and delicate. In 

 the right valve there are two moderately thick, rather prominent teeth ; 

 the one behind the beak is shorter than the other, with a more abrupt 

 posterior slope; they are separated from the slightly thickened margin 

 by a deep groove and from each other by a large notch or angle, the 

 sides of which form an angle of about 90. On the thickened margin 

 there is a thin, rough, shallow ligamentary furrow both in front of and 

 behind the beaks. In the left valve there is an elongated, thin, and not 

 very prominent, tooth-like elevation on each side of the beak; they are 

 nearly equal in size and separated by a very broad angle. 



Length of the largest specimen, about 2.4 mm. ; height, about 1 .8 mm. 



A few separate valves, off Cape Hatteras, North Carolina, in 14 to 17 

 fathoms, 1884. 



