CYAMUS CETIT. 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 firmly 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 antenna, 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 branchie. 
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 
