' Maryland Geological Survey 523 



Mesomphalus iiartleyi n. sp. 

 Plate XCV, Figs. 22-24; Plate XCVI, Figs. 1-3 



Description. — Carapace averaging 2.00 mm. in length, 1.30 mm. in 

 height, and a complete example exhibiting the ventral pouch, 1.00 mm. in 

 thickness. Valves moderately convex, rather variable in shape, but gen- 

 erally approaching an oblong subquadrate outline. Ventral portion of 

 valve in specimens supposed to represent the female form occupied by an 

 elongate sausage-shaped pouch. Central part of valve Math a small pit 

 flanked by two small rounded nodes. Surface finely reticulose, with the 

 center of each area marked by small papilla. 



Mesomplialus Iiartleyi presents an aspect so different from any asso- 

 ciated ostracod, and in fact any other described form, that there seems no 

 necessity for comparison. The specific name is in honor of Mr. Frank 

 Hartley, of Cumberland, Maryland, who was kind enough to collect wash- 

 ings for us from the Coeymans limestone at that place. 



Occurrence. — Helderberg Formation, Keyser Member. Cumber- 

 land, Maryland ; Keyser, West Virginia. 



Collections. — Maryland Geological Surv^ey, U. S. National Museum. 



Mesomphalus submarginata n. sp. 

 Plate XCVI, Figs. 4, 5 



Description. — The valves of this species suggest young specimens of 

 the associated Mesomphalus Iiartleyi, but close comparison reveals the fol- 

 lowing differences: First, the valves are smaller, less convex, more 

 elongate, and less oblique than the average specimens of the type of the 

 genus. Second, the surface in M. submarginata is more finely granulose. 

 Third, the posterior node is almost obsolete, and, lastly, the flange seems 

 to be incomplete, being absent on the posterior end. 



Length of left valve 0.9 mm. ; width 0.55 mm. ; greatest height 0.22 mm. 



Occurrence. — Helderberg Formation, Keyser Member. Cumber- 

 land. 



Collection. — U. S. National Museum. 



