ACADEMY OF SCIENCES. 299 



Scammon. Specimen of Cryptomorphite, from the Borate Mining 

 Company. Several species of Shells, from Henry Hemphill. 



Dr. A. W. Saxc made some remarks on the periodicity of the 

 California flood seasons, and their probable dependence upon the 

 exhibition of the spots on the sun's surface. 



On the Parasites of the Cetaceans of the N. W. Coast of Amer- 

 ica, with Descriptions of New Forms.* 



BY W. H. DALL, U. S. COAST SURVEY. 



Among the parasites most widely known as infesting the cetacea, two classes 

 inay be recognized, viz : those which are true parasites deriving their subsist- 

 ence from the animal upon which they are found, such as the Pycnogonoids and 

 Cyami ; and those which are merely sessile upon the animal, and derive no 

 nourishment or other benefit from it which might not equally well be furnished 

 by an inanimate object, such as the various cirripedes. 



No Pycnogonoids have yet been reported from the cetacea of this coast. 

 Brief descriptions of the species of Cyamiis found upon the California Gray, 

 the Humpback and the Arctic Bowhead whales, were submitted by me to the 

 Academy at a recent meeting. I may here add to those descriptions a few facts 

 since obtained, and bearing upon the species described. I have, through the 

 courtesy of Capt. Scammon, been able to examine a large number of Cijami 

 obtained at Monterey, Cal, from the Humpback, [M. vermbilis. Cope). They 

 are all of the same species as that (C suffusiis) described by me as parasitic 

 upon that whale ; a fact which tends to confirm the hypothesis that each species 

 of whale has its own peculiar parasites, and that there is rarely more than one 

 species of Cymnus found upon one animal. The females, which were unknown 

 at the date of my description, now prove to resemble the male in every respect, 

 except in regard to the sexual organs, and in being a trifle more slender in 

 form. 



Among the cirripedes, TubkineUa has not been reported from these waters, 

 (though it may be found in the Ochotsk sea, generally situated in the so-called 

 " bonnet " of the baleen whales) nor is the Chelonobia known to have been ob- 

 tained from any of the whales of this coast. The genera known from the north 

 Pacific waters are Coronula, an allied form which I believe to be uncharacter- 

 ized, and Otion or a closely allied form. 



SES SILI A. 



Coronula, Lam. 



Coronula, Lam. An. s. vert. v. p. 387. 



Coronula balmnaris, Lin. sp. Lam. Ann. du Mus. I p. 468, pi. 30, figs. 2 — 4, 

 This species, or one very closely allied to it, was obtained by the late j\Ir, 



* Published in advance, Dec. 18, 1872. 



