THE COAST OF CALIFORNIA. 141 



fers from P. Oeylonicus in the form of the cephalic veil, 

 the square truncated anterior and bluntly rounded, poste- 

 rior extremity. 



Plocomorphorus has but four pairs of branched lateral ap- 

 pendages between the tentacles and the posterior end of the 

 body one pair of which lies between the plumose bran- 

 chise and the tentacles while Cabrilla has four pairs of 

 lateral appendages between the branchiae and the tentacles 

 and a single additional pair behind the branchiae. It has, 

 therefore, five pairs in addition to those on the veil. 



The lateral appendages of Plocomorphorus are not rep- 

 resented by Alder and Hancock, 1 as having structures cor- 

 responding to the highly retractile bodies at the tips of the 

 lateral appendages of Cabrilla. These lens-shaped bodies 

 have been observed by me in several genera and from their 

 prominence it seems not unreasonable to regard them as 

 highly important organs. They recall in their general ap- 

 pearance otoliths, and it seems possible that they are or- 

 gans of special sense. 



CHIOR^EA LEONTINA Gould. 



(PLATE VI, FIG. 2.) 



This Nudibranch described by Gould in the " Mollusca 

 of the Wilkes Expedition" and again mentioned by Coop- 

 er 2 was collected at Monterey. My specimens closely re- 

 semble Gould's figures and descriptions and are much 

 younger than his. Dr. Cooper describes the head of his 

 specimens as " nearly conical" and "the branchial processes 

 five on each side larger than represented in Gould's figure, 

 imbricated and decumbent." The "head" of my speci- 

 mens is unlike that of those described by Cooper from 

 Santa Barbara, and is rounded like Gould's specimen from 



1 Indian Nudibranchiate Mollusca, Trans. Zool. Soc., London, Vol. v, 1866. 

 a Proc. Cal. Acad. Nat. Science, Vol. in, p. 60. 



