COMPARISON WITH ALLIED SPECIES. 613 



From a geographical stand-point there is no a priori reason 

 for their identity, they occupying entirely distinct drainage 

 basins, which have had no connection since comparatively re- 

 mote geological times. Their geographical position, indeed, 

 considered in relation to the present distribution of their 

 nearest allies, as well as to their peculiar environment, is one 

 of the most interesting facts in their history. The Baikal Seal 

 is an inhabitant of a fresh-water lake, while the waters where 

 the other finds a home are only to a slight degree salt. Neither 

 of these remote interior seas has had any recent connection 

 with the Polar Seas, where alone the nearest affines of these 

 Seals are now found. If their oceanic connection was south- 

 ward (as was most likely that of the Caspian Sea), at the remote 



either of his skulls of Pkoca fcetida, but its small size is explainable on the 

 ground of its immaturity. He himself states that his specimen of the 

 Baikal Seal weighed in the flesh only "3iPud" (126 pounds), while the 

 weight of the Baikal Seal, as he says he was informed by the Seal-hunters, 

 ranges from "8 zu 10 Pud" (288 to 360 pounds). Radde's evidently erro- 

 neous estimate of the age of his specimen is pointedly noticed by Dr. Dy- 

 bowski, who, in referring to the fact of young Seals being often mistaken 

 for old ones, adds, " wie es G. Radde gethan hat, der ein 7-8 monatliches 

 jimges Thier fiir ein 3-4 jiihriges ausgiebt."* 



In 1873 Dybowski described the species with admirable fullness, including 

 its external and cranial characters, giving figures of an adult and a young 

 skull, together with a detailed account of its external characters, of not 

 only the adult but young of various ages. He, moreover, was the first to 

 positively claim its specific distinctness, and it is an open question whether 

 Ms name baicalensis ought not to supersede Gmelin's long previously imposed 

 name sibirica. 



According to Dybowski, these Seals are pretty common in Lake Baikal, 

 but there is rarely opportunity for observing them in summer. The native 

 hunters informed him that they are often seen and shot in the months of 

 July and August on the rocky southwest shore, by lying in wait for them 

 behind rocks. It is during these months that the rutting time occurs, and 

 the young are born in January and February, so that consequently the 

 period of gravidity must be reduced to about six or seven months. The 

 young are said to depend for sustenance exclusively upon the mother's milk 

 for about four months. The lake becomes closed with ice in January, and 

 from that time till the middle of May a period of about four months the 

 Seals remain wholly under the ice, but have their breathing-holes through 

 which they obtain air. About the end of March or beginning of April, af- 

 ter the deep snows have become melted by the sun, the hunters seek out 

 these breathing-holes by means of dogs especially trained for the purpose, 

 and capture the Seals in nets placed in the breathing-holes. Arch, fur Anat. 

 ft. Phys., 1873, pp. 121-125. See further Bell's account of their capture about 

 the middle of the last century, already cited (anted, p. 612). 

 * Arch, fur Anat. u. Phys., 1873, p. 122. 



