THOMPSON: METAMORPHOSES OF HERMIT CRAB. 
153 
General Account of the Metamorphosis. 
The eggs and young of Eupagurus are very sensitive. Zoeae 
were hatched in confinement with great difficulty and as they invari¬ 
ably died in a few hours it was necessary to collect all material 
directly from the auftrieb. Even zoeae collected in this way could 
not endure more than one moult and although the later phases were 
much more resistant, they were nevertheless delicate as compared 
with the young of many other Decapods. 
The most vital factors in rearing crab larvae seem to be cleanli¬ 
ness and an -even, moderate, water temperature. The following 
method for rearing the young, although not original, is recorded 
here because it was by far the most satisfactory of those tried. In 
the end it was exclusively used. The young were kept in covered 
dishes of clean sea-water which was in sufficient volume to render 
unnecessary the use of algae for aeration. The water was changed 
daily, or in hot weather oftener, and to ensure a constant tempera¬ 
ture the dishes were partly immersed in running water or suspended 
in large aquaria. Diatoms, collected with a fine net or scraped from 
submerged objects, were the most satisfactory food, but animal food 
was also given. 
Woods Hole offers especial advantages for the study of crusta¬ 
cean development. Strong currents prevail in the neighboring 
waters, and one of these rushes past the wharves of the Fish Com¬ 
mission station during part of each tide and a large “tow net” may 
simply be suspended in this current and emptied at convenient inter¬ 
vals. Also, at those times when there is a paucity of animal life in 
the water, the numerous “ slicks ” caused by conflicting currents 
and back-sets, may prove an excellent resource, as the plankton is 
concentrated in these areas. 
Zoeaphase .— The zoeae of longicarpus and annulipes (pi. 4, fig. 
1-4) have the characteristic Pagurid form: without carinae or 
spines; with long, straight rostrum; hind angles of carapace pro¬ 
duced; swollen compound eyes, and third maxilliped rudimentary at 
time of hatching. The transparent body is pigmented with con¬ 
tractile scarlet and yellow chromatophores, and the eyes are black 
with yellow pigment diffused over the surface. No trace of a 
median eye can be found. The stomach and intestine are usually 
■clean, as but little food is taken during the phase. The livers con- 
