852 CRETACEOUS PALEONTOLOGY. 



Sub-order BRACHYURA. 

 Family DROMIAOAE 



Genus TETRACARCINUS Weller. 



Tetracarcinus subquadratus Weller. 

 Plate CXI., Figs. 16-19. 



1905. Tetracarcinus subquadratus Weller, Jour. Geol., vol. 13, 



p. 328, figs. 4-6. 

 1905. Tetracarcinus subquadratus Weller, Geol. Surv. N. J., 



Ann. Rep. State Geol. for 1904, p. 136, pi. 15, figs. 



4-6. 



Description. Carapace subquadrangular, length and breath 

 nearly equal, the dimensions of two individuals are: length, 12.3 

 mm. and 14.4 mm.; breadth, 12.5 mm., and 14 mm. Dorsal 

 surface convex longitudinally and transversely, the sides curving 

 abruptly downward to a nearly vertical position, marked by two 

 longitudinal and two transverse furrows. Rostrum short, with 

 a deep, longitudinal, median furrow. Extending backward from 

 the posterior extremity of the median furrow of the rostrum, 

 the two longitudinal dorsal furrows diverge from their anterior 

 point of origin to the junction with the anterior transverse fur- 

 row, and then converge until they nearly meet again at the 

 posterior margin of the carapace, enclosing a longitudinal, 

 median area, which is not crossed by the anterior transverse fur- 

 row, and across which the posterior transverse furrow is less 

 strongly defined than in its lateral limbs. The lateral limbs of 

 the transverse furrows become less well defined towards the 

 margin of the carapace, the anterior ones curve slightly back- 

 ward toward their distal extremities, while the posterior ones 

 have a slight forward curve, so> that the two together, with the 

 longitudinal furrows, enclose a pair of slightly convex, subovate 

 areas. From the antero-lateral margins of each of these sub- 

 ovate areas two slight, gently curved tuberculose ridges or lines 



