Zoeal Stages and Glaucothoe of Trizopagurus magni ficus — Provenzano 
465 
now a pair of fine plumose setae submarginally 
on the dorsal surface of the telson. The uropods 
consist of unarmed and nonarticulated endo- 
uropodites and setose exo-uropodites, each of 
which bears 8-10 marginal setae and 2 sub- 
marginal ones ventrally. There is a small ventral 
spine on the posterior margin of the sixth 
abdominal somite. 
The antennule consists of a long peduncle 
with an articulated segment terminally which 
will be the dorsal flagellum. Proximal to the 
articulation there are 2 long plumose setae in 
place of 1 in the previous stages and 3-5 short 
simple setae. Usually there is evident a simple 
lobe which will become the ventral flagellum 
and which bears a plumose seta. 
The antenna has 11-13 plumose setae on 
the scale and the endopodite (which has 
elongated considerably) has lost its 2 long and 
1 short plumose setae and replaced them with 
a single terminal process which appears to be 
a single flexible seta. 
The mandibles have added teeth. 
The maxillule has 7 or 8 setae on the proxi- 
mal endite and now the tiny seta occasionally 
present on the proximal segment of the endo- 
podite in earlier stages is missing. 
The maxilla bears 9-11 plumose setae on 
the scaphognathite, the endopodite carries a 
total of 6 or 7 setae. The basal endites each 
carry 4 or 5 setae. The distal coxal endite 
may have 3—5, the proximal coxal endite usually 
has 8 or 9 setae. 
The first maxilliped is basically unchanged 
but a third seta has been added to the medial 
margin of the proximal segment of the endo- 
podite. 
The second maxilliped is essentially un- 
changed. 
The third maxilliped is little changed except 
for a slightly greater development of the endo- 
podal lobe. The terminal seta of this lobe is 
sometimes missing. 
Fourth Zoea 
There is considerable variation in setation 
and relative degree of development of appen- 
dages in the fourth zoeal instar. Some individ- 
I 
II 
Fig. 5. Trizopagurus magnificus. Top , the maxillule of zoeae I-IV; bottom, the maxilla of zoeae I-IV. 
