ZOOLOGY. 51 



that these huge seals return, in some instances at least, year after year to the same localities. 

 They leave the Farallones in November, and return in May, being absent about six months. 

 How far they migrate during that interval we have, at present, no means of determining. The 

 one from which the skull was taken was estimated to weigh about a ton.&quot; 



PHOCA ? 



Seal. 



This seal penetrates San Francisco, San Pablo, and Suisan bays, and even follows up the 

 Sacramento river for some distance. 



While duck shooting on San Pablo bay, we were many times amused, and sometimes a little 

 startled, to see a round head, as large as that of a man, suddenly and silently raised above the 

 water near us, and a pair of goggle eyes, just enough human to make them horrible, staring at 

 us, recalling all sorts of stories of strangled innocence rising to confront the murderer. Usually, 

 after taking a good look at us, the head would sink as silently as it rose, leaving us in a pleasant 

 state of uncertainty whether it was ghost or demon that had formed the apparition. After a 

 longer or shorter interval that bullet head and goggle eyes would appear on the other side of 

 the boat, rising and sinking in the same ghostly way, and giving no hint, but leaving to the 

 imagination what might be appended to this curious head piece. 



A similar apparition startled me one quiet Sabbath morning when sitting on the trap rocks 

 at the Dalles of the Columbia ; the more, as I should as soon have expected to see a whale as a 

 seal at that distance from the Pacific and above the Cascades. 



DIDELPHYS CALIFOKNICA, Bennett. 



California Possum. 



BAIRD, Gen. Eep. Zool. 1857, 233. 



Guided only by my own observations, and by what I could gather from verbal testimony, I 

 should have said that the opossum does not exist in California or Oregon. We have, however, 

 the positive evidence of other witnesses that it does exist there ; and, therefore, my negative 

 evidence goes for nothing unless as an indication of its rarity. 



On the light volcanic soil of southeastern Oregon, over which we travelled for days together, 

 a surface which takes a track almost as well as snow, though I looked carefully for the tracks of 

 the opossum, so peculiar that they could hardly be mistaken or overlooked, I never saw it in all 

 that region ; nor did any of our party. 



I am therefore convinced that if the opossum exists west of the Eocky mountains, it is much 

 more rare than in the eastern States. 



SCIUEUS FOSSOR, Peale. 



California Gray Squirrel. 



Sciurusfossor, PEALE, Mamm. and Birds U. S. Ex. Ex. 1848, 55. 



AUD. &. BACH. N. Am. Quad. Ill, 1854, 264 ; pi. cliii, f. 2. 

 BAIKD, Gen. Rep. Mammals, 1857, 264. 



Sciurus heermanni, LECONTE, Pr. A. N. Sc. Phila. VI, Sept. 1852, 149. 



SP. CH. Size of 8. vulpinus, but more slender. Tail vertebrae as long as the body ; with the hairs, much longer. Five 

 upper molars. Above, grizzled bluish gray and black ; beneath, white, without any differently colored separating line. 

 Tail black, with the exterior white ; the whole under surface finely grizzled. Back of the ears and adjacent tuft on the 

 occiput, chestnut. 



This large and handsome squirrel inhabits the pine forests of all parts of California in which 

 pine forests exist. We did not observe it in any part of Oregon, and if it is found there it 



