Description of a Species of Caligus. 227 
apparently dead; but on bringing them. into a room not ie 
45° F., they have soon resumed their usual activity. When th 
temperature has been as high as 60° F., they have generally died 
in the course of a short time. This may be owing in part to the 
deterioration of the air in the water, arising from the decomposi- 
ton of the animal matter contained in it. They die almost im- 
mediately when thrown into fresh water. 
Although the imperfect descriptions of the European Caligi, by 
early authors, have been improved by subsequent investigators, 
still, in consequence of the obscure structure of these animals, 
their characters are yet very inaccurately described. We have 
therefore been unable to satisfy ourselves fully, that the species 
of this coast is distinct from the European. Yet, as many of the 
characters stated respecting the foreign species, do not apply to 
ours, we have ventured to propose it as new, under the name 
given at the head of this article.** The following eae to- 
gether with the accompanying plates, it is hoped, will enable the 
future investigator of the European individuals to Mes in regard 
to their identity. 
The results of our investigations have shown, that many of the 
errors of authors are of the most fundamental character. Among 
the principal of them, we find that a front pair of cups, serving 
for the attachment of the animal, have been mistaken for its 
_ eyes ;—the exserted ovarian tubes have of late been considered 
the respiratory apparatus ;—and what is still more essential, as it 
affects the late classification of the Crustacea, the mouth is sup- 
posed to be a sucker, whereas it contains large dentated mandi- 
bles, and other manducatory organs, appertaining to the maxillated 
species. This last character has been proved to belong also to 
the Argulus, another of the Siphonostoma, or Crustacés Suceurs, 
in an article on that animal, in this Journal, Vol. xxx1, 1837. 
* We find in a folio volume by M. Duhamel du Monceau, entitled Traité Géné- 
rale des Pesches, mpccLxxui, Paris, at page 294, a description of the Caligus found 
on the Salmon, accompanied by drawings, which, if at all accurate, show that the 
that we have seen are so evide ently inaceurate, or so destitute of details, that we 
would not venture to ray an opinion from them 
