Descriptio7i of a Species cf Caligus. 227 



apparently dead ; but on bringing them into a room not above 

 45° F,, they have soon resumed their usual activity. When the 

 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 Cahgi, 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 description, to- 

 gether with the accompanying plates, it is hoped, will enable the 

 future investigator of the European individuals to decide 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 Crustaces Suceurs, 

 in an article on that animal, in this Journal, Vol. xxxi, 1837. 



* We find in a folio volume by M . Duhamel du Monceau, entitled Traitd Gdnd- 

 rale dcs Pesches, mdcclxxiii, Paris, at page 294, a description of the Caligus found 

 on the Salmon, accompanied b}^ drawings, which, if at all accurate, show that the 

 species are not identical. The same conclusion may be drawn from Desmarest's 

 figures in his Gen. Consid. des Crustac6s, if they can be relied on. Other figures 

 that we have seen are so evidently inaccurate, or so destitute of details, that we 

 would not venture to form an opinion from them. 



