THE STOMATOPODA OF PORTO RICO. 
By ROBERT PAYNE BIGELOW, 
Of the Massachusetts Institute of Technology. 
The report herewith presented relates to the Crustacea of the order Stomatopoda 
collected by the Fish I lav f in the waters of Porto Rico during the investigations of 
the U. S. Fish Commission in the winter of 1898-99. Collections were made at 19 
dredging stations in the harbors and off the coast of Porto Rico, and many specimens 
were picked up by collecting parties in shallow water upon the coral reefs and shoals. 
The collection consists chiefly of two common species, Gonodactylus cerstedii Hansen 
and Pseudosquilla ciliata Miers. The three other species represented are Squilla 
intermedia Bigelow and two new species, Lysiosquilla jplmnata and L. maiaguesensis. 
The Stomatopoda may be distinguished from the other malacostracous crustacea 
by the fact that the stalked eyes and first pair of antenna? are borne upon distinct 
movable segments. The carapace is small, leaving four thoracic segments exposed 
behind it, and the rostrum is separated from it by a mobile joint. The second pair 
of thoracic limbs are very characteristic of the group, being developed into the large 
raptorial claws, in which the terminal segment (daetylus) closes upon the penultimate 
one (manus) like the blade of a penknife. The next three pairs of limbs, although 
smaller, are of the same pattern, and it is only the last three pairs of thoracic limbs 
that are used for walking. The abdominal appendages bear tufted gills, except the 
last pair (uropods), which are armed with a strong prolongation of the basal segment 
ending in one or two spines, and act with the telson as a powerful tail tin. 
For definitions of the technical terms used and for synopses of genera and species 
not represented in the present collection the reader is referred to the report on the 
Albatross collections (Bigelow ’94) and to the more recent memoirs listed on p. 160. 
I wish to take this opportunity to express my obligations to Prof. H. C. Bumpus 
for his kindness in granting me every facility for the study of this collection at the 
marine laboratory of the United States Fish Commission at Woods Hole. 
Figs. 2, 3, 4 were drawn by Miss McKnew; the other figures by the author. 
Genus GONODACTYLUS Latreille. 
Diagnosis . — Species of this genus are distinguished by the possession of a flexible joint between 
the sixth abdominal segment and the telson; a strongly built and highly convex hind-body; the 
daetylus of the raptorial claw being dilated at the base, without lateral teeth, and with a sharp inner 
edge that fits into a groove on the manus. 
Larval form . — A Gonerichthus Brooks, recognizable by the following characters: Eyes stalked; 
appendages i-vn and xiv-xvii present in the earliest stages; telson usually quadrate or hexagonal in 
general outline, slightly wider than long, longer than outer spine of uropod and notched on the median 
line, and with never more than four intermediate denticles; body elongated, carapace narrow, shallow, 
not infolded, without prominent ventro-lateral angles, posterior lateral spines close to dorsal median 
line and at least half as long as carapace; never any trace of lateral teeth upon the raptorial daetylus. 
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