CYAMUS CETI. 89 



fourth segments furnished with large foliaceous plates, 

 forming an incubatory sac. 



We have no precise details of the locality and notice 

 of capture of this species beyond the general statement 

 of its being found on the whale in the British seas. 

 British specimens exist, however, in the British Museum, 

 as well as in the Hopeian, Stephensian and Westwoodian 

 collections, now in the Oxford Museum, &c. 



On some of the females which we have examined, we 

 have found the young fixed fii"mly to different parts of 

 the body, about one-twelfth of an inch long, distin- 

 guished from their parents by the proportionally larger 

 size of the head (with which the following segment is 

 confluent), the shorter antenme, and especially by the 

 size of the first pairs of legs, which are equal to the 

 following, all being small, and much less strongly dilated 

 than in the adult state, and also by the small rudimental 

 size of the branchiae. 



M. Roussel de Vauzeme informs us that the species of 

 Cyamus to which he gives the name of C. erraticus, and 

 which we have regarded as the true Linnean C. ceti, 

 differs considerably in its habits from the other species 

 of the genus which he had observed. The former species 

 attaches itself at the base of the tubercles of the different 

 parts of the head, fixed upon the smooth skin in the inter- 

 vals between them, and but rarely mingling with Cyamus 

 ovalis. They, however, wander about over different parts 

 of the body, or hide themselves in the folds of the eye- 

 brows, the commissure of the lips, navel, genital and 

 anal parts. They also especially attach themselves to 

 wounded parts of the body, and on one occasion 

 M. Roussel found a whale injured by the swordfish, the 

 suppurating wound of which had attracted a vast number 

 of individuals of this species. The structure of the 



