428 
PACIFIC SCIENCE, Vol. VII, October, 1953 
pendages present; sixth, seventh, and eighth 
thoracic appendages represented by small 
buds; abdominal appendages all present, with 
small gills attached to exopods; uropods be- 
ginning to form; sixth abdominal somite with 
two small submedian spines; telson well 
developed, beginning to assume adult con- 
dition with two well-developed spines on 
distal margin and distinct submedian and in- 
termediate denticles. 
As with the first stage, all the specimens 
have been collected from regions where S. 
oratoria is either known or thought to be 
present. Innumerable specimens have been 
taken in plankton tows in the waters around 
Oahu throughout the year. They may fre- 
quently be found in the stomach contents of 
the yellowfin tuna, Neothunnus macropterus. 
STAGE 3 (Fig. 22c) : By the time the larvae 
have reached this stage, they have gained 
further adult characteristics. Sixth, seventh, 
and eighth thoracic appendages fully devel- 
oped; uropods with adult characteristics, basal 
portion elongated into two spines and small 
rounded lobe between them, exopods with 
eight spines, as yet immovable, along their 
outer margin; telson more adult-like in ap- 
pearance; no longitudinal carinae on body; 
carapace still very transparent, no indication 
of facies of adult carapace showing through 
chitin. 
At this time the specimens measure 45 to 
60 mm. in length. This stage forms a con- 
spicuous part of the plankton and has been 
taken in plankton tows from the surface down 
to a depth of 200 meters. 
There are no specimens beyond this stage 
in the collections. It is rather unusual that 
no postlarval forms have been found in which 
the adult characteristics such as the body cari- 
nae, the adult carapace, and the teeth on the 
raptorial dactylus are present. I assume from 
this that the larvae become bottom dwellers 
immediately after they lose the larval carapace. 
Squilla sp.^ 
Fig. 22d 
Approximately 200 specimens of this alima 
larval stage were taken in night light stations 
at Honolulu Yacht Harbor, Oahu. They close- 
ly resemble the preceding larval types, but, 
as only one stage was collected, it is impossi- 
ble to assign the specimens to an adult species. 
Carapace covers less than 0.3 total length of 
body, very narrow; all appendages fully de- 
veloped, gills represented by small buds on 
exopod of pleopods; telson very large com- 
pared with other body segments, composing 
about 0.25 total length of body; fully devel- 
oped uropods, bearing five spines along outer 
margin of exopod, with basal portion elon- 
gated into two spines, inner shorter than 
outer. 
Pseudosquilla ciliata 
Figs. 25a- f, 24a-c 
STAGE 1 (Fig. 25a): Brooks (1886) has il- 
lustrated a pseudozoea larva similar to this 
stage. This represents the earliest larval stage 
of members of the genus 'Pseudosquilla. By 
observing the relative changes in the other 
stages, I have come to the conclusion that 
these are the young of P. ciliata. Typical 
erichthus larva with only first and second 
thoracic appendages present; abdomen with 
four pairs of biramous pleopods, without 
gills; telson nearly rectangular, with eight 
small denticles between submedian denticles; 
eyes not borne on long stalks as in alima of 
Squilla as articulation is close to ophthalmic 
somite; antennules present; antennae appear 
as small buds; merus and ischium of raptorial 
claw with terminal articulation, propodus fine- 
ly pectinate along upper margin, dactylus 
composed of single spine; carapace trispinous 
anteriorly, posteriorly bearing two long spines 
reaching second abdominal somite; may or 
may not have small zoeal spine between two 
posterior spines; carapace longer than broad, 
its lateral margins depressed. 
