THE FOSSIL STALK-EYED CRUSTACEA (39 



tero-lateral margin sinuous both in dorsal and in lateral view, and 

 marked by a granulate line for about two-thirds the distance from 

 the lateral spine. Posterior margin sinuous, slightly concave at 

 middle and having a continuous raised line of granules. 



Areolation of carapace: The mesogastric and cardiac regions are 

 well delineated, the hepatic region depressed; anterior end of meso- 

 gastric region a little raised. A blunt, branchial ridge runs inward 

 and slightly forward from the lateral spine and bends gradually 

 backward to a point just behind the broadest part of the mesogastric 

 region where it forms a large tubercle. This tubercle is one of three 

 making an almost equilateral triangle,-^ the second tubercle situated 

 at the inner branchial angle, and the third in an almost transverse 

 line with the second but a little farther forward; it is more acute 

 than the others, almost sharp to the touch and has a long posterior 

 slope; the innermost tubercle is less elevated than the others. The 

 cardiac region has a low elevation each side of the middle. Eleva- 

 tions of carapace granulated. In front of branchial ridge a sub- 

 parallel row of about six low tubercles. 



Orbits and ventral aspect : The orbit is deep and high in propor- 

 tion to its width, the eye does not fill it ; lower margin more advanced 

 than upper, denticulate, spine at inner angle very stout. Ischium 

 of outer maxilliped (pi. 17, fig. 6) suboblong, divided into two un- 

 equal parts by a very deep, sinuous groove, which anteriorly ap- 

 proaches the inner margin. Surface of merus very uneven. Exog- 

 nath about half as wide as endognath. Abdomen of male triangular 

 from the third segment to the tip ; third to fifth segments fused ; the 

 third and fourth together are depressed in the middle and on either 

 side form a smooth, rounded elevation; sixth segment twice as wide 

 at base as its greatest length ; terminal segment subtriangular, broader 

 than long. The surface of the abdomen appears almost smooth, the 

 lower surface of the carapace, the sternum, maxillipeds and begin- 

 ning segments of the chelipeds are more or less finely granulate. The 

 small peg on the second sternal segment w^hich serves to hold the 

 abdomen in place, is visible on the right side of one male and is very 

 sharp. In only one specimen is any portion of a female abdomen 

 visible, and there only two segments, perhaps the fifth and sixth; 

 the fifth (if such it be) is shorter and has more arcuate outer mar- 

 gins than the sixth. 



Chelipeds and legs: Chelipeds unequal, stout, granulate; merus 

 with a subdistal groove above; carpus uneven, with a strong inner 

 spine. Manus swollen, a low, longitudinal ridge through the middle 

 of the outer surface (pi. 17, fig. 3), the ridge gradually flattening 

 out toward the fingers; granulation fine and on either side of the 

 ridge reticulated; upper surface (pi. 17, fig. 4) flat or slightly con- 



23 From which the specific name is derived. 



