240 CRABS OF THE FAMILY PERICERIDZ—RATHBUN. 
Chelipeds slender, not so long as the first pair of ambulatory legs. 
Merus subeylindrical, with a row above of four spines and a few tuber- 
cles; inner, outer, and inferior surfaces, each with a longitudinal row 
of tubercles. Carpus obscurely tuberculate, with a crest of four tuber- 
cles above. Hands compressed, upper and lower margins parallel in 
the male, tapering in the female. Fingers meeting along their inner 
edges, evenly dentate. 
Ambulatory legs slender, decreasing successively in length. Dactyls 
slightly arched, shorter than the penultimate joints. 
Dimensions of a male in millimeters: Length, including rostrum, 83; 
width, without spines, 70; length of cheliped, 122; length of first am- 
bulatory leg, 144; length of fourth ambulatory leg, 81. 
RECORD OF SPECIMENS EXAMINED, 
Gulf of ergata U. 8. Fish Commission, 1889: 
Cat. No. | | station. | Lat. N. af Long. W. Wee PS itetes Nature of bottom. 
| | ecu 
apart 
| 16069 | 3016 29 40 | 112 2 57 00 76 59 en. M. 
16070 3015 | 2919 | 112 50 00 145 | 54.9 | br. M. 
16071 dat 3011 | 28 07 | 111 39 45 71 57.9 | tne. gy. S. brk. Sh. 
This species is named after the Hon. Marshall McDonald, U.S. Com- 
missioner of Fish and Fisheries. 
Libinia spinimana, sp. nov. 
Plate xxx. 
Carapace the same general shape as the preceding, studded with nu- 
merous Sharp spines and covered, excepting on the distal half of the 
spines, with a dense pubescence, the hairs being lighter and shorter 
than in macdonaldi. The depressions and grooves are placed similarly 
to those of macdonaldi, but are more shallow. There are about twelve 
prominentspines on the median line; five on the gastric region, twoon the 
genital, two on the cardiac, two on the intestinal, and one on the pos- 
terior margin. On the frontal region there are two or three small spines 
placed longitudinally on either side of a broad shallow groove. On 
each gastric region there is a spine which forms a transverse line with 
the second median spine. There is no continuous line of lateral spines, 
but near the margin there are prominent spines arranged as follows: 
Three on the hepatic region, the longest at the external angle, the other 
two on the anterior border and directed forward; two near the anterior 
portion of the branchial region, and two farther back. There is an 
irregular row of small spines near the posterior margin. The entire 
carapace is covered with spines of different sizes, varying with the 
specimen. 
Rostrum but slightly detlexed, flattened vertically, composed of two 
Sharp divergent spines coalesced for about one-third their length. 
Orbits as in macdonaldi; prieocular and postocular spines more prom- 
inent than in that species. Basal antennal joint shaped as in macdon- — 
