Maryland Geological Sukvey 363 



Description. — Manns long and narrow, parallel-sided, its thickness 

 more than half the width, about equally convex on the two sides, smoothish, 

 showing scattered punctures and under a lens a very fine punctulation ; on 

 both sides of the hand a row of three or four small pointed tubercles run 

 lengthwise along the median convexity; lower edge bluntly biangular. 

 Pollex nearly double the width of the dactylus, pyriform in section, with 

 a row of tubercles along the grasping edge. Dactylus oval in section, also 

 bearing pointed tubercles opposed to those on the pollex. 



Length of manus as broken 35.3 mm. ; width 11.5 mm. ; thickness 7 mm. 



Types are Xo. 10.120 collection of Wagner Free Institute of Science, 

 and consist of an imperfect manus with broken dactylus in place, a frag- 

 ment of the pollex, apparently of the same specimen, and a fragment of 

 another hand of larger size, width 11 mm., thickness 9 mm. They were 

 exposed by breaking hard nodules which occur in the clay at Lenola, New 

 Jersey. Another broken manus is in the collection of the Philadelphia 

 Academy from the deep cut of the Chesapeake and Delaware Canal in 

 Delaware. 



The species is readily recognizable by the long, narrow shape of the 

 hand and the minute punctulation of the surface, the biangular lower 

 edge of the pollex and hand, etc. 



Occurrence. — Matawax Formation. Deep cut of the Chesapeake and 

 Delaware Canal, Delaware. 



Collections. — Wagner Free Institute of Science, Academy of Natural 

 Sciences of Philadelphia. 



Family CALLIANASS1DAE 



Genus CALLIANASSA Leach 



Callianassa mortoni Pilsbry 



Plate XI, Figs. 1-3 



f Callianassa antiqua Otto, 1870, Credner. Zeitsch. d. deutsch. geologisch. 



Gesell., Bd. xxii, p. 241. 

 Callianassa mortoni Pilsbry, 1901, Proc. Acad. Nat. Sci., Phila., p. 112, pi. 



i, figs. 1-7. 

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



Pal., vol. iv, p. 849, pi. cxi, figs. 1-15. 



