SHAI--HMBRYOS. 5 



that the young pass at once into the water. In another animal of the same species, 

 born in the Zoological Gardens in London, the hair was got rid of immediately after birth, 

 and with it the young animal formed a sort of nest upon which it lay for some hours. 



The foetal hair of Leptonychotea seems to approach in quality more nearly to that 

 of Holichcerus, as described by Turner, rather than to that of Plioca. The young of 

 Halichoerus do not change their first hair until about three weeks after birth, and then, 

 but not till then, do they take to the waier. Dr. Wilson (loc. cit.} gives some 

 interesting particulars in this connection with regard to the habits of the young of 

 Weddell's Seal. He says that after birth the young " lay on the ice at the mouth of 

 the blow-holes which the parents kept open for the purpose of procuring food. The 

 young were born in a thick and woolly coat of dull ochre-grey and black showing 

 something of the markings which would appear later on in the adult. The coat began 

 to drop off at the end of fourteen days, and by the end of a month the moult had 

 finished. The young seal, attired now in a very handsome coat of glossy black and 

 silver hair, could for the first time enter the water and take a share in finding its own 

 food. It is suckled for a variable time on the ice. It takes about two years to arrive 

 at maturity and the size increases considerably for many years." 



Wright has suggested that the character of the fcetal hair on those seals which 

 take to the water immediately after birth may present certain differences from the 

 hair of those animals which enter the water only after some interval of time. The 

 facts just stated appear to confirm the truth of this suggestion. And further, 

 Leptonychotes, both in habit and in the quality of the first developed hair, more 

 closely resembles Halichoerus than Phoca. 



The vibrissae on the upper lip are arranged in four rows. They are distinctly 

 visible in embryos of 98 mm. in length (No. 6), so that by the time the body hairs 

 begin to appear the animal has whiskers of considerable length. The tufts of long 

 hairs which are attached a little distance above the inner angle of the eye do not 

 make their appearance until later, when the animal has attained a size of 158 mm. 

 (No. 20). 



Eyes, nose, and ears. The eyelids were firmly adherent to one another along their 

 edges even in the oldest foetus. Whether they remain closed until the time of birth, 

 or even after, as in some other carnivores, I am unable to say. In the foetus of a Grey 

 Seal (IMichcerus grypus), "about three months from the completion of its term of 

 intra-uterine life," described by Turner, the palpebral fissure was not closed. As 

 already stated, there is a narrow line of dark pigment along the margin of either lid 

 from quite an early age. The pupils are circular. 



The external nares are, throughout the series, in the form of crescentic slits, the 

 concave margin being directed outwards, and are covered by a valvular fold of skin. 

 The nares are placed upon the anterior surface of the snout, and look forwards. Not 

 even in the oldest specimen have they assumed the dorsal position characteristic of the 

 Phocidse. In the latest stage the nose is covered with short hairs, and there is no 



