" PACKARD.) REPRODUCTIVE HABITS OF BRANCHIPODIDA. 427 
The further growth of the larva brings about an elongation and seg- 
mentation of the body. The latter begins from the base of the body, 
finally extending to its tip. 
A nearly perfect circular dise is seen on the anterior part of its dorsal 
side; this is the cephalic scute (carapace). 
With the subsequent gradual development this scute retreats, confin- 
ing itself in the adult to the occipital part of the head. In the base of 
the second pair of antenn 
a rather large meandering 
gland is seen whose outlet is 
right below the first saber- 
shaped flat bristle. This is 
the so-called antennal gland, 
whose presence has been as- 
certained in most members of 
this family of Crustaceans. 
Below the middle of the pic 50_strept : a 
front of the larval head han gs os Sth rman Beauols Wadia ine Perris ot ae 
down a short broad fleshy tles dropped, the remainder are shortened. 
lobe, which in live specimens under the microscope is seen occasionally 
to lift and lower again. This is the labrum, which we also find in the 
adult in a somewhat reduced state. The median pigmented eye on the 
front of the larva is sessile, very simple, having but one pair of “‘ corpora 
vitrea” placed laterally. The Nauplius can distinguish light from dark, 
but cannot discern the exact outlines of objects with it. 
The mandibular basal process of the third larval leg is transformed 
into a mandible with a curry-comb-like dentation, and makes its ap- 
pearance at the time when the fourth or fifth pair of branchipeds begin 
to bud. 
A 9° of Streptocephalus texanus had 22 flat acinaciform, long maxil- 
lary teeth, and a very minute curved spine at the lower end. ‘The first 
of the teeth at the upper end has 14 spines, all the rest have 8 or 9; 
the uppermost of them in each case being about twice as long and much 
stouter. 
Transverse segmentation of the body always preceeds the lateral 
budding of the branchipeds. 
The furea or terminal fork of the abdomen very early begins to bud 
in the shape of two latero-terminal protuberances with two short min- 
ute spines, and a little later another smaller lateral spine is formed. In 
larve of about 3.5™" in length, five such spines have made their ap- 
pearance on each of the two protuberances. The number of spines, 
with the middle one the longest, gradually after each moult, multiplies 
until the typical furea of the adult is attained. Between the first pair 
of branchipeds and the mandibulary palpus at an early age the two 
pair of maxille are formed, the first pair of which has in the adult 
Streptocephalus the characteristic form as illustrated by Plate XXXIV, 
fig. 7. In none of the numerous specimens examined by me could I ever 
find a mandibulary palpus in the adult. 
When of about 3 or 4"™ in length, the second pair of antenne are re- 
placed by another form, the old one gradually degenerating. First the 
posterior, together with the two curved basal hooks, then the middle, 
and finally also the terminal long bristles and inner branch drop off 
from the inner side of the second antennz. In the interior of the second 
antenna, near its base, an exuberant growth of cells takes place at this 
time (Fig. 50). On the outer side, near the base, three protuberances are 
seen, from each of which groups of hyaline, rather stout and short spine- 
like bristles arise. Their bases can be seen to originate from the deeper 
