THOMPSON: METAMORPHOSES OF HERMIT CRAB. 
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Th ird Zoea. 
Uropods present, and sixth abdominal segment distinct; 
exopods with seven setae; rudiments of the gills on second, 
third, and fourth limbs. Length, 3.5-4 mm. 1 
Fourth Zoea , Metazoea. 
Limb rudiments very large, dactylus of cheliped distinct; 
rudimentary pleopods present; gill rudiments for chelipeds 
present; right cheliped obviously larger than left — this 
condition of the chelipeds may possibly date from the third 
zoea; maxillipedal exopods with eight setae; uropods sym¬ 
metrical ; mandibles without palpus rudiment. Length, circa 
4 mm. 1 
Faxon (’82) described four zoea stages identical with these four, 
and it is likely that he studied larvae belonging either to Fupagurus 
longicarpus or to annulipes. Other investigators have not recorded 
so many stages. None of them describes the second zoea, unless one 
of the figures, no. 52, in Claus’s “ Zur Kenntniss der Kreislaufs- 
organe ” (’84), corresponds to it. But it should not be assumed 
that this stage is typically absent from the zoea phase of the various 
Pagurids, for it closely resembles the first stage and might readily 
be overlooked. My third zoea corresponds to Rathke’s (’40, ’42) 
“young of one and three-fourths lines” and to Claus’s ('61) 
“spateres Stadium.” The other writers make no mention of a 
similar stage. The metazoea has been repeatedly noted. Rathke 
(’40, ’42) termed it, “young over two lines long ”; Bate (’68), “ what 
we take to be the second stage”; Claus, “Mysisstadium ” (’76), 
“Metazoea” (’85); and Sars ('89) ,“last larval stage,” “last stage 
before moult to adolescent stage.” 
Postzoeal phase. — The postzoeal phase includes only one stage, 
the fifth or glaucotlioe (pi. 4, fig. 5). The larva is now 2.8-3.3 
mm. long and is Macruran in form with symmetrical abdomen and 
with pleopods on the second to the fifth segment. The uropods 
are asymmetrical as in the adult, and the thoracic appendages are on 
the whole adult in type and proportions. A few tubercles on the 
posterior thoracic limbs and on the uropods (pi. 6, figs. 19, 20; pi. 7, 
fig. 31.) represent the future tuberculated areas. The sternum of 
1 Including as they do the larvae of two species, all the measurements have 
an unduly extended range. 
