STYLOCHEIRON CARINATUM. 293 
Stylocheiron carinatum G. O. Sars. 
Plate 12, figs, 6a-6d. 
Intermediate Furcilia-Stage (figs. 6a—6c).— The frontal plate with rostrum 
constitutes a rather large triangle almost as long as broad and with the lateral 
margins somewhat concave and the end very acute; the dorsal keel of the cara- 
pace is low and placed much behind its middle; the lateral margins of the 
carapace are without any tooth. 
The eyes have the lower section well developed, while the upper is small.— 
The antennular peduncles are rather slender; the process from first joint reaches 
a little beyond the end of next joint; second joint almost twice as long as broad, 
somewhat shorter than the third; flagella unjointed, upper flagellum much 
shorter and thinner than the lower which is about half as long as third peduncular 
joint— Antennae and maxillipeds showing the usual larval development; 
two anterior pairs of thoracic legs rudimentary. 
First pair of pleopods with the exopod setiferous; the two following pairs 
are very oblong, undivided; the posterior pairs rudimentary, scarcely visible 
below the margin of the lateral plates— Sixth abdominal segment as long as 
the sum of the two preceding segments.— The uropods reach much beyond the 
middle of the telson.— Telson is four and a half times as long as broad, with the 
distal part somewhat narrower than the proximal; the terminal margin (fig. 6c) 
is long, with seven rather long, naked spines, increasing in length from the 
median spine to the subangular pair; the intermediate pair of postero-lateral 
spines are very long and strong, a little longer than the inner pair and both pairs 
with about five or six fine spines along a good part of their inner margin; the 
proximal third pair of the postero-lateral spines are rather small. 
The specimen is 2.8 mm. long; it is somewhat poorly preserved so that I 
may have committed some inaccuracy in the appendages on fig. 6a.— The 
specimen is from Sta. 4611, October 18, 1904, Surface. 
Last Furcilia-Stage (fig. 6d).— The triangle formed by the frontal plate 
and rostrum in the main as in the preceding stage, but the lateral margins are 
nearly straight; the dorsal keel of the carapace is placed a little more forwards 
but still considerably behind the middle.— Eyes a little more developed.— 
Antennulae with the process from first peduncular joint a little shorter and the 
still undivided lower flagellum conspicuously longer than in the former stage.— 
Endopods of first and second pairs of thoracic legs more than half developed, 
with the full number of joints, and the relative size, shape, and tegumental 
