34 ANIMAL PARASITES AND MESSMATES. 



seen on the true whales of the north and of the temperate 

 regions, on the Megaptera, and on several Catodonta, and 

 that none are found in the Balenoptera. Mr. Dall has 

 just noticed some on the singular Grey Whale of Cali- 

 fornia. In general, we may say that each cetacean 

 which harbours them, has its own species. Are they 

 parasites or messmates ? If we are to believe Eoussel 

 de Vauzeme, they feed on the skin itself of the whale, 

 the remains of which, it is said, are found in their 

 stomach. According to this naturalist, the parts of the 

 mouth are not adapted for suction, and the stomach 

 contains ruminating apparatus. We think that a fresh 

 examination is necessary before this question can be 

 determined. The Cyami seem to us to live on the 

 whale, as the Arguli and the Caligi do on fish'; and if 

 these living creatures derive their nourishment only from 

 the mucous products secreted by the skin, we may ask 

 whether they ought not to be classed in a separate cate- 

 gory, for they ought not to figure on the list of paupers. 

 We have found the orifice of the Tubicinella covered with 

 cyami of every age, and their abundance in this place 

 seems to indicate that their food was not supplied to 

 them by the skin of their host. Mons. Ch. Lutken has 

 recently published a very interesting monograph on 

 these curious animals; according to him the Cyamus 

 rhytinse, which was thought to proceed from a piece of 

 the skin of a Stellerus, appears to have been found on 

 the skin of a whale. 



The Picnogonons, the nature as well as the kind of 

 life of which has been so long time problematical, 

 deserve to be ranked among messmates, at least during 

 their youth ; in fact, after being hatched, they live on 



