1879.] 149 [Kingsley. 
gin behind the lateral tooth. Sub-hepatic regions with spiniform 
tubercles. Basal joints of antennae with hairs and short setae. 
Chelipeds short and very slender, hand naked, the other joints and 
ambulatory feet above with spines and spiniform tubercles inter- 
spersed with short hairs. Dactyli of four posterior pairs curved, 
acute. 
Florida. A. S. Packard, Jr. 
A male gives the following measurements. 
Length of carapax, 10 mm.; breadth, 10.5 mm.; ratio, 1: 1.05. 
This species differs from M. affinis, acuticornis, and Holderi in hav- 
ing the rostral horns spined instead of obtuse and unarmed; from 
M. coronatus in the broader carapax and non-acuminate horns; from 
M. spinosissimus in the simple character of the antero-lateral teeth ; 
from M. aculeatus and verrucosus in having the basal joint of antennae 
two spined ; from MM. hispidus in the absence of sulci,and presence of 
eranulations on the carapax, the more spiniform marginal teeth and 
longer rostral horns; from M, pleuracanthus in the granulate carapax 
and the character of rostrum, and from WM. verrucosus in the rostral 
horns and the acute marginal teeth. 
Mithrax triangulatus. 
Mithraculus triangulatus Lockington, Proc. Cal. Acad., vir, 73, 
(1876). 
Carapax with the regions very protuberant and tuberculate, es- 
pecially the outer part of the branchial, the gastric and cardiac. 
Rostrum short, bifid, horns extending beyond the orbits, with the 
margins crenulate. Inner angle of orbits prominent, acute; superior 
margin with two nearly obsolete fissures, external hiatus moderate; 
below, a fissure at the junction of the basal joint of antennae. 
Antero-lateral margin three lobed, and below the lobes perpendicular. 
Below with two tubercles beneath the orbit, one small one on the 
subhepatic region and three rows of tubercles on the perpendicular 
surface of the branchial region, the lower of which extends obliquely 
forward to the angle of the palatal region. Basal joint of antennae 
very broad with two teeth, (not spines). Chelipeds moderate, meros 
sub-cylindrical with a few small tubercles; carpus nearly smooth, 
rounded; hand inflated, smooth, fingers moderately gaping, extrem- 
ities denticulate, a strong basal tooth on the dactylus. Remaining 
feet small, spino-tuberculate. 
Gulf of California. W.N. Lockington. 
Length of carapax, ¢, 12.4 mm., 2, 11.1 mm.; breadth, ¢, 11.5 
Hime s 11.0 mm.* ratio, ¢, 1: .93, ¢, 1: .99. 
