VOL. III.] Nattiral History of the Farallones. 151 



ZOOLOGY. 



The birds of the Farallon Islands have been collected and recorded 

 until they are tolerably well known; but, so far as I am aware, no 

 attempt has hitherto been made to collect representatives of all the 

 forms of life resident upon this little group of rocks. The trip made 

 by Mr. J. W. Blankinship and myself, on July 3, 1892, was limited 

 by the necessities of the case to a stay of only two whole days upon 

 South Farallon Island, but we availed ourselves of the opportunity 

 to collect in all departments of natural history to the fullest extent 

 possible. In so brief a stay it was manifestly impossible to do more 

 than skim over the surface in most branches, but the lists, even in 

 their incomplete form, may be of value in showing the character ot 

 the life of the spot. Larger collections might have been made of 

 certain classes had not Mr. Blankinship devoted a large part of his 

 time to the study of the geology and botany of the island, while I 

 was engaged in observing the habits of the birds and in making 

 collections of the young for future investigation. 



The results of the survey were disappointing in one respect, viz. : 

 that no evidence was obtained indicating that any of the animals of 

 the islands have become differentiated from mainland forms. It may 

 be that fuller collections, or more careful elaboration of the material 

 obtained, would show some slight variations, although, if present at 

 all, they are undoubtedly very incipient in nature. It would seem 

 as if the wingless beetles and the one batrachian of the islands would 

 be effectually isolated upon a bare rock thirty miles from the main- 

 land, but it is impossible to say that these forms have not been ac- 

 cidentally introduced in recent times through the agency of man. 

 Unfortunately, we have been unable to have some few of the spiders, 

 insects, etc., identified, so these forms are necessarily omitted from 

 the list. 



Mr. Wm. E. Ritter named the two following radiates: 



Aster ias ochracea. 



Sirongylcce7iirotiis purpuratus. 



MOLLUSCA. 



The following list of the mollusca thus far recorded from the Far- 

 allones has been kindly compiled by Dr. J. G. Cooper, from his 

 published and unpublished lists, together with the collection of the 

 expedition: 



