PORTO RICAN ISOPOD A. 
171 
spines and numerous setae, about half as long as the ramus itself; external ramus narrow, with about 
eight spines and numerous sefce on the posterior and outer margin. 
This species is close to A. in-sularis, from which it differs in its greater hairiness. 
Two specimens. Station 6079, 20 fathoms, 5 by 2.3 mm. 
£GIIL£. 
Key to Porto Rican genera and species. 
a. Peduncle of first antennse dilated anteriorly and not hidden by front margin of head: flagellum consisting 
of more than 0 joints; head not much produced in front of eyes; epistome large; maxillipeds 
consisting of 6 or 7 joints JEga 
Only Porto Rican species.. *. A. ecarinata 
an. Peduncle of first antenme not dilated, more or less hidden by the projecting front of head, flagellum of 6 
joints or fewer; head projecting well in front of eyes, front triangular; epistome minute or rudi- 
mentary; maxillipeds consisting of I joints .- Rocinela 
Only Porto Rican species If. signata 
-32ga ecarinata Richardson. 
“Body elongate and narrow. Length more than three times greater than breadth. Surface 
punctate. Frontal margin of head Insinuated, the acumen separating the first pair of antenme. Eyes 
large and oblong and situated at a small distance apart. First pair of antenme extending almost to 
flagellum of the second pair of antenna-; the first two joints of peduncle very broad; second joint 
extending anteriorly over the third joint, reaching almost to the extremity of that joint; third joint 
two-thirds narrower than first and second; the flagellum containing nine articles. Second pair of 
antenme extending to middle of the first thoracic segment; flagellum containing ten articles.” 
“Epimera of all the thoracic segments narrow, the first two being rounded, the other four more 
acute at their extremities. First two pairs of prehensile legs rather stout; third pair less so, and the 
propod us of this pair is furnished with a large cultriform process. Five spines are present on the merus 
of all three pairs. Gressorial legs slender and sparsely spinulose.” 
“All the abdominal segments are visible in a dorsal view. Terminal segment broad and 
posteriorly bisinuated, forming three teeth with rounded extremities; its surface entirely smooth.” 
“Outer branch of uropods narrower and somewhat shorter than the inner branch; its extremity 
is rounded. Inner branch obliquely truncate and c.renulate on posterior margin. Uropods and 
terminal abdominal segment all fringed with a few hairs.” 
One specimen, station 5052, 310 fathoms, 37 by 11 mm. This specimen was found on deck 
after the dredge was landed, and probably did not come from the bottom. 
Rocinela signata Schiodte & Meinert, 
Female, body oval, about 2.25 to 2.50 times as long as broad. The front is triangular and 
obtusely produced. The fifth and sixth thoracic segments are longest, the fourth and seventh are 
somewhat shorter, the second and third are shortest, and the first is less than the seventh and a little 
shorter than the head. The first pleonic segment is narrower than its successors, and more or less 
hidden dorsally, its posterior margin bisinuate; the next three segments are wider and subequal in 
length; the fifth segment is narrow, partly hidden laterally by its predecessor, and longer dorsally. 
Telson subtriangular, about two-thirds as long as broad, its dorsal surface usually ornamented 
with three bands of pigmentation, the median one straight, longitudinal, the lateral ones transversely 
arched; a row of pigment spots on each side near the tip, parallel with the margin; posterior border 
crenulate and furnished with setae. Eyes small, separated by about one-third of breadth of head. Firs! 
antennae reaching to about middle of last joint of peduncle of second antennae, flagellum 4-jointed. 
Second antennae reaching to middle of second thoracic segment, peduncle extending to posterior 
border of eye, flagellum 11 to 12 jointed. Epistome minute or absent. 
Epimera rather large, slender, posteriorly produced and acutely angled, the last reaching nearly 
or quite to the middle of second abdominal segment. 
Uropods hardly reaching to end of telson, inner ramus narrow, not much wider than the outer 
and a little longer; both branches rounded posteriorly, their borders crenulate and furnished with 
setae, with spines on their external borders. 
Specimens from Culebra, 12.5 by 5 mm. 
