90 
CRUSTACEA. 
Two other species of Hippolite were also taken at Monterey, California, but their distinguishing 
features are less marked than the preceding ; they may be thus characterized : 
27. Hippolite Layi. 
Hip. rostro acuminato, supra multi-serrato, ante medium subtus quadri-serrato. 
Long. corp. unc. 2£. Color ruber. 
Plate XXVII. Fig. 3. Rostrum auctum. 
28. Hippolite affinis. 
Hip. rostro antennis superioribus breviore y supra multi-serrato , ante medium subtus sex-serruto. 
Long . corp. 1£. Color ruber. 
Plate XXVII. Fig. 4. Rostrum auctum. 
In addition to the difference in the serrations of the rostrum, which probably varies in different 
individuals of the same species, (although the number was constant as above quoted in three speci- 
mens of each species which were preserved,) Hip. Layi has a longer and narrower rostrum, extending to 
the extremity of the superior antennae-, the inferior seta of these antennae is also proportionably longer. 
Hip. affinis has a spine above the eye, at the root of the rostrum, which is wanting in the Hip. Layi; 
whilst this species has the fifth and sixth abdominal segments unispinous interiorly on each side. 
Hip. affinis having the sixth segment only so armed. 
From the Alplieus Polaris of Sabine (Zool. Appendix to Parry’s Voyage, p. 238, pi. 2. fig. 5.), 
which is a Hippolite of Leach, and from the species characterized by Ihe latter author in the Mala- 
costraca Podopli. Brit., the above species differ in the forms and proportions, as well as in the serra- 
tions of the rostrum. 
Qrdo STOMAPODA, Latr. 
Section UNIPELTATA, Latr. 
Genus SQUILLA, Latr. 
29. SQUILLA ciliata. Leach, MS. n. s. 
Sq. flava, leevis , pedipalpis primis inermibus ciliatis, pollicibus secundorum tridentatis. 
Long. corp. unc. 2. lin. 8. 
This species has a smooth and polished body, of a yellowish colour. The penultimate segment 
of the abdomen has six spines, two of which are placed on the superficies, and four at the posterior 
margin. On the last segment are three carince, which end in spines; at the posterior margin are six 
spines, of which the middle two are moveable. The exterior of the natatory lamella: of the tail is 
serrate along the onter margin, and unispinous at the extremity, to which a round ciliate plate is also 
attached ; the inner lamella has two spines at the extremity. 
The first pair of pedipalpi is long, slender, and terminates in a flattened oval plate, unarmed 
and ciliated. The pollex or moveable joint of the second pair has three elongated spines. 
In the proportions of the antenna, and in the form of the natatory caudal lamella:, this species 
resembles the Squilla Chiragra of Fabricius ; but differs from it in having spines on the thumb, and 
from every other described species of Squilla in having the first pair of feet-palpes unarmed, 
