402 PROCEEDINGS OF THE NATIONAL MUSEUM. 



OBOLUS (LINGULELLA) ELLSI, new species. 



Shell small, broad ovate in outline, with the ventral valve obtusely 

 acuminate and tlie dorsal valve broadly rounded; valves api)ear to 

 have been moderately convex, Judging from the appearance in the sili- 

 ceous shale. The surface of the shell is marked by rather strong con- 

 centric Hues and strite of growth, the striae indicating a slightly 

 lamellose surface. Very tine radiating stria' occur on the surface of 

 the inner layers of the shell. A ventral valve 3.5 mm. in length had a 

 width of 2.75 mm,; the dorsal valve is a little shorter than the ventral 

 valve. 



Purtial casts of the interior of the ventral valve show a very clearly 

 detined area that extended as a shelf on each side of the rather dee}), 

 narrow i)edicle furrow; portions of the casts that till the undercut may 

 be observed in several specimens; the llcxure lines are narrow, shiirj), 

 and situated well out toward the lateral margins. Tiie cast of the 

 visceral area of the ventraJ valve extends about one third the distance 

 from the area to the anterior margin; it is not well defined, and no 

 traces of muscle scars have been detected; of the vascular system only 

 the base of the main sinuses are shown in any of the casts. 



Ohfiervations. — Tiiis very pretty little species is closely related in 

 form to 0. {Ij.) rotundatus^ and comparison should also be made with 

 the more rotund variety of 0. {L.) ferrugi neus. It occurs in association 

 with Acroihcle prcUosa [Obolella prctiom Billings). 



The specific name is given in honor of Dr. R. W. Ells reports, whose 

 fine work on the geology of a portion of the Province of Quebec unrav- 

 eled the stratigrai)hic relations of the Lau/on slates in which the 

 species occurs. Dr. Ells also guided me to the h)cality at which the 

 species occurs. 



Formation and locality. — Upper Cambrian, Upper Sillery (Lauzon 

 of Logan), Chaudiere River, Grand Trunk Railroad bridge, Province of 

 Quebec, Canada. 



Ti/pe.—'So. 27315, U.S.N.M. 



OBOLUS (LINGULELLA) EUGLYPHUS, new species. 



General form ovate, with the ventral valve subacuminate, and the 

 dorsal valve broad ovate in outline. There is some range of variation 

 in tlie outline of the valves; the convexity of the valves is fairly strong, 

 and is nearly the same in each. A ventral valve 11 mm. in length has 

 a width oC 8 mm.; convexity, li mm.; and a dorsal valve D mm. in 

 length has a width of H mm.; convexity, 1.^ mm. 



The outer surface of the shell is marked by strong concentric lines 

 and striic of growth, and a complex system of lamellose striiv. of the 

 type of those on (). (L.) ella. The striic have a transverse direction, 

 are irregular, and sometimes inosculating. The stria> are a little 

 coarser tlian those on the surface of O. {L.) ella, and finer than those of 

 0. [L.) aurora. They are also less irregular than those of (). {L.) ella, 



