160 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



and indicates a large excrescence, perhaps a spine, on the dorsal sur- 

 face; 3 pits only are visible in the outer row, the middle pit is in 

 transverse line with the anterior pit of the other rows, while the 

 anterior pit of the outer row is not quite in line with the two behind 

 it. Either side of the pair of small submedian gastric pits there is 

 a large cavity. The furrows separating the branchial from the 

 gastric and cardiac regions are indicated by sinuous ridges. 



Judging from the proximity of the rows of pits, this carapace is 

 narrower in proportion to its length than in other species of Mursia. 

 This together with the evidence of a strong prominence near the 

 postero-lateral borders points to a genus different from any described. 



MURSILIA, new genus. 



The manus resembles that of Mursia, but lacks the crest or ridge 

 on the inferior margin. . 



Type of the genus. Mursilia ecristata, new species. 



MURSILIA ECRISTATA, new species. 



Plate 57, fig. 27. 



Type-locality. Gatun beds. Gatun formation. Miocene series. 

 "Robert T. Hill, collector. 



Holotype.Cat. No. 135219, U.S.N.M. 



Measurements. Length of palm, 9.8 mm., height of palm, 7.4 mm. 



Represented by only one specimen showing the right palm and a 

 portion of the wrist. Palm short and high. Surface finely and 

 rather distantly granulated on the upper half of the outer surface 

 and at the proximal end ; more closely granulated on the lower sur- 

 face. There are 9 large tubercles arranged in 3 oblique, subparallel 

 rows ; the tubercle at the inferior proximal corner is much the largest, 

 is flattened above and has a raised rim; between it and the next 

 tubercle in the horizontal row, but a little below, there is a smaller 

 tubercle. Below the distal tubercle of the horizontal row of 3, and 

 nearer the inner than the outer surface there is a small tubercle. On 

 the upper margin there are 7 narrow, thickened teeth similar to those 

 of Calappa. . Below the sinus between the fifth and sixth teeth 

 (counting from the wrist) there is a low tubercle; also one on the 

 base of the second tooth. A part of a tubercle near the beginning of 

 the immovable finger is visible. 



The outline of the wrist is defined, but very little of the surface 

 remains ; a small piece near the distal upper corner is granulated like 

 the upper half of the palm. 



The tuberculation of the manus or palm resembles that of Mursia, 

 the dentation of the upper margin is nearer that of Calappa, while 



