K. BROWN ON THE SEALS OF GREENLAND. 37 



-waddling, or sliuffling kind of motion — the animal leaning over 

 on one anterior extremity, and then rolling back on the other 

 to make a similar use of it, using them thus alternately and the 

 muscles of the spine continuously, chiefly those of the lumbar 

 region and erectores spincc.^ In carnivorous animals the intestinal 

 canal is shorter than in graminivorous species, yet there are 

 exceptions, for the Sloth has a very short intestine, and the Seal 

 a very long one. I have measured the length of the intestine 

 of Pagophilus grcenlandicus, and found it to vary between 50 

 and 56 feet in length. 



It is said that the livers of the Seals at Novai Semlaj and in the 

 southern seas possess poisonous properties ; this is not the case 

 with the livers of any of the Greenland Seals, for they are often 

 eaten, and I never knew of any bad effect ensuing. The lym- 

 phatic glands are well developed, these glands being of great 

 size, though not numerous, it being common to find only one in 

 each axilla and groin. In the young Seals the lymphatics of the 

 neck are subject to disease, which appears to be analogous to, if 

 not indeed true scrofula : the glands swell, suppurate, and pour 

 out a purulent discharge, and the animals subject to this disease 

 do not increase in size. 



Many theories have been adduced to account for the Seal's 

 capability of remaining with impunity so long below water. That 

 ofBuffon and the physiologists of his time was long celebrated: 

 from their finding the foramen ovale open in a few instances, 

 they twisted an exception into a rale, and accounted for it by this 

 foetal peculiarity. Dr. Wallace considers that this theory is 

 erroneous, and from numerous observations he is satisfied that 

 the open foramen must be very rare, for in only one of the Seals • 

 which he examined did he find the foramen ovale unenclosed to 

 within a line of the aorta. That of Blumenbach and Houston 

 has been also brought forward, viz., that venous sinuses are to be 

 found in the liver and surrounding parts, and that the large veins 

 have been observed to be enlarged and tortuous ; these have been 

 supposed to act as reservoirs for the returning venous blood while 

 the animal is diving under the water. But this theory carries 

 inconsistency in itself. The venous system on the whole, and 

 not in any particular part, unless in the vena cava, from the 

 pressure excited on its walls, is greatly enlarged ; but this arises 

 from the great quantity of blood these animals possess. But, even 

 supposing the existence of these Acnous sinuses, and that the 

 animal will remain below the surface for twenty or twenty-five 

 minutes (though I never saw them remain longer below the 

 surface than fifteen minutes, and from five to eight is the common 

 time), are these sinuses large enough to contain the full quantity 

 of blood that may return in that period from the capillary system ? 

 The reply is certainly in the negative. Does the heart's action 

 diminish in rapidity, or come to a full stop } In that case there 

 would be no need of these sinuses. "What, then, are their uses ? 



* For a fuller account of the mechanism of motion in Seals, see Pettigrew, 

 Trans. Linn. Soc, vol. xxvi. ; and Murie, Proc. Zool. Soc, 1870. 



