100 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Rostrum not reaching to end of peel uncle of inner antennae. Carapace very rough, with linn, sharp 
spines which are longer on dorsal than on lateral regions. Abdomen thickly armed with outwardly 
projecting spines. Third pair of legs long, abundantly armed with spines; propodus with about six 
rows of larger spines and many smaller and less regular intermediate ones. 
Total length, 55.2 mm. ; length of carapace, 20.2 mm. ; of abdomen, 35 mm. ; of rostrum to posterior 
margin of orbit, 6 mm.; of telson, 10.5 mm. 
Between San Antonio Bridge and San Geronimo, San Jnan, Porto Rico (G. M. Gray). Also occurs 
at Dry Tortugas, Fla.; Cuba; Jamaica; Bahamas, to a depth of 36 fathoms; Port Castries, St. Lucia; 
near Monosquillo, Albatross station 2142, lat. 9° 30' 15" N., long. 76° 20' 30" W., 42 fathoms; Bermudas; 
East Indies and South Pacific. 
Tribe PENtEIDEA. 
Body laterally compressed. First three pairs of feet usually chelate and not very strong; fourth 
and fifth pairs always simple. Gills dendrobranchiate. 
Family PENtEIDTE Milne Edwards, 1837 (Pencens). 
Carapace at sides deeply produced and carried farther back than in the median dorsal line; 
rostrum laterally compressed, this part at least being carinated. Of the segments of the pleon the first 
three are usually not longitudinally carinate, but the three that follow are almost always much so. 
The sides of the first are produced so as to overlap the hind lateral margin of carapace and the front 
lateral margin of second segment. Telson generally dorsally flattened or grooved. Eye-stalks usually 
tw' '-jointed. First antennae with two multiarticulate flagella; the first joint of the peduncle flattened 
to "eeeive the eye-stalk and laterally strengthened on the outer side by a spine-like process, on the 
inner by an unjointed appendage often fringed with hairs. Second antennae with a broad, thin 
foliaceous scale and a long flagellum. Mandibular palp never more than two-jointed. Third maxilli- 
peds long and pediform. Both the second and third maxillipeds and the three or four following pairs 
of appendages carry epipodal plates. First three pairs of trunk-legs chelate and similar, the second 
longer than the first, and the third longer than the second. Extruded ova not definitely attached 
to the appendages of the mother prior to hatching, as in most other Maerura. 
Key to the Porto Rican genera of the family Penxidiv. 
A. Carapace without a median dentate crest. 
B. Antcnnular flagella shorter than carapace. 
('. Endognath of the first maxilla greatly elongated and segmented Penseus 
O'. Endognath of first maxilla short and unsegmented Parapenxus 
B'. Antennular flagella longer than carapace Xipluipeneas 
A'. Carapace with a median dentate crest Sicyonia 
Genus PEN7EUS Fabncius. 
Penieus Fabricius, Entom. Syst., Suppl., 3S5, 1798. 
Distal segment of mandibular palpus much larger than proximal, very broad, and not prolonged 
into a narrow tip. Endognath of first maxilla greatly elongated and segmented. Endopod of 
maxilliped slender and composed of four segments, the exopod lamellar and unsegmented; both pairs 
of gnathopods have well-developed epipodsand large exopods; all the pereiopods have small exopods, 
but only the first, second, and third are furnished with epipods; a well-developed pleurobranchia 011 
the fourteenth somite. Antennular flagellse not longer than carapace. 
Penaeus brasiliensis Latreille. 
PenxiisMictsiliensis Latreille, Nouv. Diet. Hist. Nat., xxv, 166, 1817. 
Carapace with a high median carina extending almost to posterior margin; a deep and broad 
sulcus on either side of carina. Posterior half of carina with a median sulcus, making it. bicarinate. 
Anterior half of carina arcuate, highest part above orbit; dentate or spinous, with nine teeth, posterior 
tooth almost half-way back on carapace and remote from the others, six of which are on the rostrum 
proper. Two or three ventral teeth on rostrum. Rostrum unarmed and horizontal toward extremity. 
Hepatic spine and antennal spine, carina, and groove well marked. Cervical suture extending only 
half-way from hepatic spine to dorsal carina. A subhorizontal suture below hepatic spine. The ros- 
trum reaches almost to end of antennular peduncle. This peduncle is very short, stout, and hairy. 
Abdominal carina on fourth to sixth segments very sharp; on the sixth is a groove either side of it. 
Telson with a deep median groove and an acuminate extremity. 
