NO. 1908. :\^EW SILURIAN MOLLUSCA FROM MAINE— WILLIAMH. 387 



EURYMYELLA SHALERI, var. LONGA, new variety. 

 Plate 49, fig. 8. 



General characters as in E. shaleri, but the length nearly twice as 

 groat as tho height and the umbonal angle as low as 35° or less. The 

 typo-spocimen measures: Length 20 mm., height 12 mm., umbonal 

 angle = 35°. 



Locality. — Same as the typical forms of the species. 



Holotype.—C&t. No. 58435, U.S.N.M. 



EURYMYELLA SHALERI, var. MINOR, new variety. 

 Plate 49, fig. 9. 



General characters of botli form and proportions as in E. shaleri, 

 but averaging about half the size of typical E. shaleri. 



Type-specimen. — Length 13 mm., height 8 J mm., umbonal angle 

 about 50°. 



Locality. — Carlow Island. 



Holotype.—C&t. No. 58436, U.S.N.M. 



EURYMYELLA ANGULARIS, new spedes. 

 Plate 49, figs. 10, 11. 



Shell irregularly pentagonal in form; height four-fifths the length; 

 beak low, scarcely protruding beyond the hinge margin. Hinge line 

 long, straight, from the extremities of which the sides, both anterior 

 and ]wsterior, proceed at nearly right angles. The front margin for 

 nearly one-fourth of the height of the shell is nearly straight, thence 

 turns rather abruptly backward at an angle of 130° to the middle of 

 the ventral margin in a slightly convex line to the angular termina- 

 tion of the umbonal ridge. The umbonal ridge makes an angle of 

 about 70° with the posterior part of the hinge line. Li the type- 

 specimen the flattened area back of the main umbonal ridge is crossed 

 by a second sUghtly shorter, low ridge, neither ridge sharply defined, 

 but expressed in the slight deflection of the concentric lines, and by 

 flattening of the surfaces between them and between the latter and 

 llie jwsterior hinge margin. The termination of the second lidge 

 causes a blunt angle in the posterior margin. The surface is marked 

 by fine, concentric lines and occasional laminar foldings of tlie surface. 

 The general surface is low-convex; the umbonal region low and flat- 

 tened; the highest arching of tlie surface is subcentral. 



Dimensions of tvpe-specimen (a left valve) : Length of hinge mar- 

 gin, 22 mm.; length across middle of shell, 24 mm.; posterior height, 

 20 mm.; height of front side, 9 mm.; main umbonal angle. 70°. 



A right valve from the same locality shows the deflection of llie 

 concentric lines on the middle of the posterior slope, but the surface 



