SEAL-EMBRYOS. 



It will be seen that all these embryos, the place of capture of which is stated, were 

 obtained either at Cape Armitage or Hut Point. It is difficult from the above Table 

 to deduce any definite facts relative to the rate of growth, as, from the same locality 

 and on precisely the same date, specimens were, obtained with extreme total lengths 

 of GG mm. and 1G1 mm., a difference of 95 mm. The mean date of capture may be 

 taken as March, and the mean length of the embryos included in the above Table 

 (excluding Nos. 24 and 25, the dates of capture of which are not given) is 155 mm., 

 or, including the tail, 127 '5 mm. The average length of those obtained during 

 February (9th to 25th) is 99 mm., while that of the thirteen taken in March 

 (1st to 20th) is 149 '6 mm. Taking the mean dates in these two months as 

 February 17th and March 10th, we arrive approximately at a rate of growth of 

 50 mm. in 21 days. Supposing this to represent the rate of growth from the 

 commencement, it follows that the date of sexual pairing would be in the early part 

 of January. From these figures one may also estimate the period of mating as being 

 not less than six weeks. 



Major Barrett-Hamilton states (2) that the young of Weddell's Seal are 

 born on the ice in September. Dr. Wilson, in his appendix to Capt. Scott's "Voyage 

 of the ' Discovery,' " however, says that they were able to observe the breeding habits 

 and that the young were born " during the last week of October and the beginning 

 of November." This difference of two months may possibly be accounted for by the 

 difference in latitude. The young specimen (three months old) described by Major 

 Barrett-Hamilton was found by the ' Belgica ' Expedition in 70 18" S. Lat., whereas 

 those observed and collected by the ' Discovery ' were obtained about 78 S. Lat. 



It may therefore safely be concluded that the period of gestation in the seals is 

 not less than nine months, probably rather longer. Nine months is the time given 

 by Sir William Turner, though he does not mention the data upon which he based 

 the statement. 



It is evident that the rate of growth as estimated above for the earlier period 

 of intra-uterine life must be increased during the later periods, otherwise a young 

 animal born in the early part of November would measure but just over GOO mm., 

 which is considerably exceeded in my oldest uterine specimen. The development of 

 the hair, the descent of the testes, and other factors, lead to the conclusion that this 

 largest foetus could not have been far from completing its uterine existence. 



DESCRIPTION OF THE EXTERNAL CHARACTERS. 



Colour. With the exception of the two oldest specimens, all the embryos are 

 destitute of hairy covering and are of an ivory-white colour, due no doubt in part to 

 the action of the preservative fluid. The only pigment visible gives rise to a narrow 

 black line along the margin of each eyelid, where it makes its appearance at a very 

 early age. The two largest specimens showed considerable colouration ; in the younger 



B 2 



O 



