HISTORY OF THE NORTH AMERICAN 



PINNIPEDS. 



The Pinnipeds, or Pitmipedia, embracing the Seals and Wal- 

 ruses, are commonly recognized by recent systematic writers 

 as constituting a suborder of the order Fercv, or Carnivorous 

 Mammals. They are, in short, true Carnivora, modified for an 

 aquatic existence, and have consequently been sometimes 

 termed li Am/pMbiou8 Carnivora." Their whole form is modified 

 for life in the water, which element is their true home. Here 

 they display extreme activity, but on land their movements 

 are confined and labored. They consequently rarely leave the 

 water, and generally only for short periods, and are never found 

 to move voluntarily more than a few yards from the shore. Like 

 the other marine Mammalia, the Cetacea and Sirenia (Whales, 

 Dolphins, Porpoises, Manatees, etc.), their bodies are more or 

 less fish-bike in general form, and their limbs are transformed 

 into swimming organs. As their name implies, they are fin- 

 footed. Generally speaking, the body may be compared to two 

 cones joined basally. Unlike the other marine mammals, the 

 Pinnipeds are all well clothed with hair, while several of them 

 have, underneath the exterior coarser hair, a thick, soft, silky 

 under-fur. In contrasting them with the ordinary or terrestrial 

 mammals, we note that the body is only exceptionally raised, 

 and the limbs are confined within the common integument to 

 beyond the knees and elbows, and are hence to only a slight 

 degree serviceable for terrestrial locomotion. The first digit of 

 the manus is generally lengthened and enlarged, as are both 

 the outer digits of the pes. As compared with other Ferce, 

 they present, in osteological characters, many obvious points of 

 difference, especially in relation to the structure of the skull, 

 limbs, and pelvis, and in dentition. The skull is distinctively 

 characterized by great compression or constriction of the inter- 

 orbital portion, the large size of the orbital fossa?, in the lachry- 

 mal bone being imperforate (without a lachrymal canal) and 

 contained within the orbit, and in the presence (generally) of 

 Misc. Pub. No. 12 1 1 





