312 BULLETIN OF THE 
Just behind the eye-stalks, on the front part of the carapace, are two 
large blotches of dark pigment. Two similar pigment-spots are seen in 
most individuals on the hinder part of the carapace, and one in the 
median line of the body on the dorsal side of the second abdominal seg- 
ment. The distribution of pigment-spots varies considerably, however, 
in different individuals, 
Second Larval Stage (Pl. TL Figs. 2— 4). — After the first moult the 
larva measures 3mm, from the tip of the rostrum to the end of the 
abdomen. It now has the the same general shape as in the preceding 
stage, but the carapace is provided with a dorsal spine which is directed 
forward at the base of the rostrum, and a lateral spine on each side, on 
the anterior margin. This spine is the supra-orbital of Stimpson's 
nomenclature.* The posterior margin of the fifth abdominal segment is 
produced into a tooth-like process on each side. 
The first pair of antenne have acquired an additional (third) segment, 
but are still simple. 
The second pair of antenna are of the same shape as in the first 
larval stage, as are also the mandibles and maxillæ. 
The maxillipeds have increased in length, and the second and third 
pairs are longer in proportion to the first pair than they were in the 
foregoing stage. The first pair have gained a segment in both the inner 
Arter. Kongel. Dansk. Vidensk. Selsk. naturvid. og mathem. Afhandl. IX Deel, 
pp. 245-251, Tab. VI. Figs. 120—132. 1849), the young of Hippolyte polaris ex- 
tracted from the egg have the five pairs of walking-feet in the form of small, simple, 
jointed appendages, the first pair with the chela already formed. Five pairs of 
double abdominal limbs are also present, but no sign of the sixth or posterior pair. 
We thus see among the Caridea a very great difference in the degree of develop- 
ment in which the larvie leave the egg. At one extreme we have Pencus quitting 
the egg as a nauplius (Fritz Müller, Die Verwandlung der Garneelen. Arch. f. 
Naturg., Vol. XXIX. pp. 8 - 23, Taf. IL. 1863), at the other Hippolyte, provided with 
all the appendages of the adult excepting the last abdominal. Here the walking-feet 
are simple from the first, and the larva does not pass through a Sehizopod stage. 
Between these extremes are larve like those of Caridina (Joly), Palamonetes, eto., 
which hatch with appendages developed as far back as the third pair of maxillipeds 
inclusive, or the second pair of walking-feet, and which pass through a Mysis-stato. 
It is to be observed, however, that in the larva doubtfully referred to Hippolyte by 
Claus (Untersuchungen zur Erforschung der Genealogischen Grundlage des Crustaceen- 
Systems, pp. 44, 45, Figs, 14-18. 1876), the rudiments of the walking-feet appear 
subsequently to the earliest larval stage, — first the two anterior pairs simultaneous 
with the swimmerets (the earliest to appear of the abdominal limbs), then the three 
following pairs, Here all the walking-feet of the adult are 
split-feet in the larva. 
Proc, Acad. Nat, Sci. 
* Prodromus Descriptionis Animalium Evertebratorum, 
Phila., 1860, p. 24. 
