22 University of California Publications in Zoology [VoL. 23 
Characters.—Rostrum exceeding eyes, but falling short of antennular. peduncle; 
above ciliate and armed with nine to ten teeth, below with two small teeth near 
depressed tip; rostrum continued backward as a carina nearly to posterior margin 
of carapace and sulcate posterior to last tooth. Carapace with suleus parallel to 
and on each side of dorsal carina, continued forward from posterior extremity of 
dorsal carina onto lateral ridges of rostrum; outer margins of sulci more promi- 
nent near last rostral tooth and distinctly flared outward. Telson acute, deeply 
suleate above, and devoid of lateral spines or spinules; greatly exceeded by the 
uropods. 
Dimensions.—Length 42 mm., carapace 10 mm., rostrum 5 mm. (Kingsley). 
Of specimen examined by Holmes, length from tip of rostrum to tip of telson 
182 mm.; carapace, including rostrum, 41 mm.; rostrum 24 mm. 
Type Locality.—Estero at Realijo, west coast Nicaragua (salt water). 
Distribution—San Francisco Bay, California to Panama; Galapagos Islands. 
To a depth of 51% fathoms (Rathbun). 
Genus Benthesicymus Bate 
Rostrum short, elevated, compressed; if armed, toothed above only. Outer 
edge of basal joint of antennular peduncle armed with one or two spines; no 
scale on inner edge; antennular flagella longer than the carapace. Mandibular 
palp foliaceous, two-jointed, second joint narrower and shorter than the first. 
Exopodites of second maxillipeds much longer than endopodites; endopodites 
subpediform with last three joints more or less flexed on the merus. Exopodites 
on all the legs decreasing in size posteriorly until they become rudimentary on 
the last pair of legs. 
Key TO THE CALIFORNIA SPECIES OF BENTHESICYMUS 
I. Median carina of fifth and sixth abdominal segments terminating posteriorly 
in a small acute tooth. ; 
tanneri, p. 23. 
II. Fifth and sixth abdominal segments devoid of teeth; posterior margin of sixth 
segment raised to form a peculiar transverse ridge. 
altus, p. 22. 
Benthesicymus altus Bate 
Plate 11, figure 2 
Benthesicymus altus Bate, Ann. Mag. Nat. Hist., (5), 8, 191, 1881; ‘‘Chal- 
lenger’’ Rept., Zool., 24, Macrura, p. 336, pl. 58, fig. 1, 1888; Faxon, 
Mem. Mus. Comp. Zool., 18, 203, 1895. 
Characters.—Rostrum short, compressed, apex styliform, crest thin and armed 
with two teeth, continued back as a carina as far as the cervical groove, posterior 
to which the dorsal surface is smooth and rounded; last three abdominal segments 
much compressed, the fourth but slightly carinated, more so on the posterior half 
than anteriorly, the sixth segment with a small but decided carina, which fades 
out before it reaches the transversely elevated posterior margin. 
Dimensions.—Type, female: length 120 mm, 
Type Locality—Between Australia and New Guinea, 1400 fathoms (‘‘Chal- 
lenger’’ station 184). : 
Distribution—South Pacific; Philippines; Japan; South Atlantic, off Tristan 
da Cunha; 500 to 1900 fathoms (Bate). Gulf of Panama; west coast of Central 
