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BULLETIN OF THE UNITED STATES FISH COMMISSION. 
at several stations in the shallow sound between St. Thomas, Culebra, and Porto Rico by dragging the 
tangle over the coral bottom. The greatest depth was 20 to 23 fathoms, at station 6079, off St. Thomas. 
Life history . — Hansen (’95) identities the larval form of this species under the name Pseuderichthus 
communis. In the earlier stages it can not be distinguished from the very similar larva of Pseudosquilla 
oculata Brulle (Pseuderichthus distinguendus Hansen) . But when fully developed it may be recognized 
by its smaller size, 21 to 24 mm., and the possession of 8 distinct spines on the uropod (Hansen, 1. c., 
pi. viii, fig. 5). P. distinguendus of this size does not have the upper spines of the uropod distinct. 
When fully developed this species is longer than P. communis — over 24 mm. — and has 10 to 11 of these 
spines. 
Between this stage and the adult form there is an intermediate stage (Claus, ’71, tigs. 26 and 
27c). We might call it the monodactyla stage, for, according to Hansen, Pseudosquilla monodactyla of 
Milne-Edwards is this stage of P. oculata. The carapace has lost the larval spines and the whole 
appearance of the animal is very much like the adult Pseudosquilla; but on the dactylus of the 
raptorial claw only the rudiments of the two lateral teeth may be seen beneath the integument, and 
the telson has only the median carina, the others not being developed. In our specimens, however, 
there are slight elevations on the telson representing the lateral marginal and external pair of central 
carina?. Hansen has two specimens of this stage of P. ciliata that measure from the tip of the rostrum 
17.5 and 21.3 mm. In the present collection there are five specimens in this stage from three localities. 
They were taken in Ensenada Honda in Culebra, San Juan Harbor a quarter of a mile from Morro 
Castle with the dredge at a depth of 4 to 74 fathoms, and at station 6092 between Culebra and Vieques 
with the tangle at a depth of 16 fathoms. These specimens have the following lengths, 16, 17.5, 17.5, 
19, 19 mm. Three of them have 9 mobile spines on the uropod and two have 8. 
It is probable that at the next molt these would pass into the adult form, and that the growth at 
that time results in a thickening of the body rather than in increase in length. In fact, there seems to 
be a slight shortening of the body, for in the collection there are five small specimens of the adult 
form measuring 16, 17, 17, 17.5, and 17.5 mm., respectively, but their bodies are much thicker and 
more strongly built than the larva:' in the monodactyla. stage. One of these has 8 mobile spines on 
the uropod; the others have 9. 
Genus LYSIOSftUILLA Dana. 
Diagnosis.- — “ Stomatopoda having the sixth abdominal segment separated from the telson by a 
mobile joint; the hind-body depressed, loosely articulated, and wide; the dactylus of the raptorial 
claw without a basal enlargement and with not less than five marginal teeth; no more than 4 den- 
ticles, often only 1, between the intermediate and submedian marginal spines of the telson, which is 
usually wider than long.” 
Larval form. — A Lysioerichthus, Brooks, having stalked eyes, appendages i-vii and xiv-xvii 
present in earliest stages; telson wider than long, with never more than four intermediate denticles; 
body short; carapace large and wide, infolded on the ventral side, with prominent ventral angles, and 
posterior lateral angles widely separated from the median line; hind-body wide and Hat,. 
Lysiosquilla plumata, sp. nov. (Figs. 5 to 9.) 
Provisional diagnosis. — A Lysiosquilla having the corneal portion of the eye nearly globular and 
set obliquely upon the strong, nearly cylindrical eye-stalk; the dactyli of the raptorial claws with nine 
marginal teeth, including the terminal one; antennary scale small, less than half the length of the 
carapace; appendages to the walking legs linear; the rostrum shorter than wide, triangular, with 
rounded apex, hardly overlapping the ophthalmic segment ; the carapace smooth, nearly quadrate, 
without acute angles, posterior lateral lobes slightly produced backward; the hind-body smooth; 6 
marginal spines on the sixth abdominal segment, the intermediate pair arising slightly in front of the 
margin; the telson wider than long, convex above with 3 dorsal carinse, of which only the middle one 
ends in a posterior spine, narrow lateral marginal car i me, 6 marginal spines, submedian pair long and 
mobile, the other pairs shorter and curved slightly upward, no submedian denticles, 1 intermediate 
and 1 lateral one on each side, arising from the ventral surface of the telson and partially covered above 
by a broad lobe of the margin; uropods with a very narrow basal prolongation, angled on the ventral 
side, without serrations, and terminating in 2 stout spines, of which the inner one is the longer; and 
7 mobile spines on the uropod, the distal one not much more than half the length of the paddle. 
