THE BRACHYURA AND MACRURA OF PORTO RICO. 
79 
Family PARTHENOPIDvE Milne Edwards, 1834; White, 1847. 
Basal joint of antenna very small and embedded between the front and the floor of the orbit. 
Ohelipeds vastly longer and more massive than the other legs. 
Key to the Porto Rican genera of the family Parthenopidx. 
A. Carapace not laterally expanded over the ambulatory legs. 
B. Carapace tuberculate. 
C. Carapace convex. Pterygostomian and subhepatic regions not deeply excavated Lambrus 
O'. Carapace depressed. Pterygostomian and subhepatic regions excavated, this excavation forming, when 
the chelipeds are retracted, passages to the efferent branchial apertures Platylambrus 
B'. Carapace smooth (except for a few strong spines). 
C. Carapace high, without a strong lateral spine Solenolambrus 
C'. Carapace depressed, with a strong lateral spine Leiolambrus 
A'. Carapace more or less expanded to form a vault in which the ambulatory legs are concealed. 
B. Carapace greatly expanded both laterally and posteriorly. Pterygostomian region smooth, not ridged ...Cryptopodia 
B'. Carapace expanded laterally, but not posteriorly. Pterygostomian and subhepatic regions traversed by a 
granular ridge. Heterocrypta 
Genus LAMBRUS Leach. 
Lambrus Leach, Trans. Linn. Soc. London, xi, pp. 308 and 310, 1815. 
Carapace either broadly triangular or ovate-pentagonal with short, pointed front. Surface 
granular, tubercular, or spiny. Eyes inclosed in distinct orbits, with a suture above and hiatus 
below, the hiatus occupied by the second joint of antennal peduncle. The antennules fold obliquely. 
Antennae small; their basal joint, which is extremely short and does not reach the front, is wedged in 
between the antennulary fossa and the large lobe that constitutes floor of orbit. Buccal frame usually 
quadrangular, sometimes a little narrowed in front; completely closed by the external maxiliipeds. 
Chelipeds usually of immense size and length, out of all proportion to the short, slender ambulatory 
legs; arm and hand usually prismatic with the borders strongly dentate; fingers much shorter than 
palm and abruptly curved inward and a little downward. 
Lambrus agonus Stimpson. 
Lambrus agonus Stimpson, Bull. M. C. Z., II, 131, 1871; A. Milne Edwards, Crust. Riig. Mex., 151, 1878, pi. xxvm, f. 3, 1879 
Carapace ovate-pentagonal, about one-fifth broader than long, with rounded sides, without 
angles; a moderate postorbital constriction. Depressions between regions not remarkably deep. 
Surface coarsely punctate or eroded, with numerous granules and tubercles; the larger tubercles more 
or less spiniform and arranged as follows: Five on gastric region, of which four are near the middle in 
a transverse line, and another, larger, on median line behind them; three in a longitudinal row on 
cardiac region; one on each side of urocardiac lobe; five on each branchial region, the posterior one 
being prolonged in a spine; one on each hepatic region. The antero-lateral margin of branchial region 
is armed with six small teeth; below and behind the last three is a short denticulate crest; below this, 
a stout spine. Rostral tooth narrow and produced; a few denticles at its base on either side. Several 
spines on outer margin of orbit and a small spine on upper surface of eye. A conical tubercle on each 
side of sternum near base of chelipeds; another on coxal joint of. chelipeds. The second segment of 
abdomen has a sharp transverse crest, forming a lobe in the center and a tooth on each side. Chelipeds 
very long and slender (the arm about 1.33 times the width of the carapace), their upper surface 
finely rugose. An irregular row of dentiform tubercles near the middle of the upper surface of arm 
and wrist and nearer the outer' margin of hand; inner and outer margins of arm and wrist with similar 
tubercles. Upon the upper margin of hand a series of eighteen or twenty irregular teeth, increasing 
generally in size to a point near the fingers, when they diminish; on the outer margin four to six 
larger teeth and many intermediate smaller ones. Ambulatory legs long, for the genus (the first one 
reaching end of wrist), slender, bare, and. almost smooth, having only some faint indications of spinules 
on upper margins of meral joints. 
Dimensions of male: Length of carapace, 17.5 mm.; width, 20.8 mm. 
Gulf of Mexico; Florida Reefs and Caribbean Sea; 25 to 84 fathoms. Mayaguez Harbor, 75 to 76 
fathoms, station 6063. 
Genus PLATYLAMBRUS Stimpson. 
Platylambrus Stimpson, Bull. Mus. Comp. Zool., II, 129, 1871. 
Closely allied to Lambrus, of which it may be only a subgenus. Carapace strongly carinated or 
tuberculated, broadly triangular (considerably broader than long), with rounded sides and abroad 
