198 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
The Glaucotiioes. 
Iii the year 1880, Milne-Edwards described a small, supposedly 
adult shrimp under the name “ Glaucothoe peronii.” No one seems 
to have questioned the validity of this form as a true species, until 
the year 1864, when Muller pointed out its similarity to the post- 
zoeal stage of “ Pagurus ” and suggested that it might be a larva. 
But since that time the problems arising out of Muller’s suggestion 
have attracted the attention of several carcinologists. On the one 
hand, Bate (’66, ’68) asserted that Glaucothoe was “only a larval 
Pagurus” and Faxon (’ 82 ) simply identified his postzoeal Pagurids 
with Milne-Edwards’s genus and with the older genus Prophylax 
(Latreille, ’30) • while on the other band, Claus (’76) asserted that 
the structure of the mouth parts in Glaucothoe was adult rather 
than larval; Miers (’ 81 ) described a second species, G. rostrata\ 
and Henderson (’88) described a third species, G. carinata. 
More recently the whole problem has been re-attacked by Bouvier 
through a study of the Glaucothoes themselves and, in the year 
1891, he published the results of his work. He concluded that 
these forms were undoubtedly larval, since they lacked sexual 
orifices and opthalmic scales ; that they were Pagurid rather than 
Thalassinid and belonged to the asymmetrical Pagurids; that they 
were not a natural group, for on structural grounds G. peronii was 
assigned to Sympagurus, while G. carinata lay nearer “Pagurus or 
a related form ” ; and that they presented “ exactly all the essential 
characters of the larvae described by certain embryologists under 
the name of glaucothoes.” 
Now my research, as has been the case with the work of other 
students of Pagurid development, does not bear directly on the 
main problem presented by these peculiar crustacean forms. But 
it does involve some subordinate phases of the problem and affects 
some of the suggestions which have been put forward during the 
discussion. Two main objections have been brought against the 
“larval theory” : the great size — 10 to 20 mm.— of the Glaucothoe 
as compared with all known glaucothoe-stage larvae, and the feeling 
that if these forms were really developmental stages they would be 
more abundant. Henderson (’88) has especially laid stress on this 
latter point. It seems to me that the cogency of both of these 
objections has been overestimated. 
