366 Systematic Paleontology 



Collections. — Maryland Geological Survey, Academy of Natural 

 Sciences of Philadelphia, Wagner Free Institute of Science. 



Callianassa mortoni var. marylandica n. var. 

 Plate XI, Figs. 9, 10 



Description. — The manus resembles that of G. mortoni by having the 

 inner face (palm) much less convex than the outer. The outer face has a 

 longitudinal series of four punctures running to the base of the pollex, 

 and a series of five to the base of the dactylus; it is contracted near the 

 proximal articulation and has a group of tubercles in the crest before the 

 constriction. The lateral margins of the manus are sharp and crenulated, 

 the margin behind the dactylus being nearly straight, not deflected near 

 the proximal angle as in C. mortoni. The pollex is one-third the total 

 length of the manus, and at its base nearly one-third of the width. It has a 

 submedian crenulated ridge and an obtuse median tooth on the grasping 

 margin. The dactylus is not fully exposed, but seems to be somewhat 

 longer than the pollex. The carpus, merus, and ischium do not differ 

 materially from those parts in 0. mortoni. 



Length of hand, exclusive of fingers, 17 mm. ; breadth 12 mm. ; thick- 

 ness 6 mm. 



This race is separated from C. mortoni chiefly on account of the differ- 

 ent shape of the outer margin of the hand. In over a hundred individuals 

 seen of that species, the margin is always much more deflected near the 

 proximal angle. The type is a complete cheliped. The example from Seat 

 Pleasant is not fully identified, being imprefect. 



Occurrence. — Monmouth Formation. Brightseat (type locality), 

 Brooks estate near Seat Pleasant, Prince George's County, Maryland; 

 head of Bohemia Creek, Delaware. 



Collection. — Maryland Geological Survey. 



Callianassa conradi Pilsbry 

 Plate X, Fig. 5 

 Callianassa conradi Pilsbry, 1901, Proc. Acad. Nat. Sci., Phila., p. 114, pi. i, 



figs. 8-10. 

 Callianassa conradi Pilsbry, 1907, in Weller, Geol. Survey of New Jersey, 

 Pal., vol. iv, p. 851, pi. ex, figs. 18-22. 



