SEAL-EMBRYOS. 15 



fissuring (figs. 9, 10, 11). In the oldest specimen there is a greatly elongated lobe on 

 the left side which runs some distance backwards along the dorsal abdominal wall. 



The intestine was considerably convoluted. Owing to its brittle condition it 

 was impossible to obtain exact measurements, but the total length of the gut was 

 approximately 2 ' 5 metres in the oldest foetus. The large intestine was not sacculated, 

 the diameter being the same throughout the length of the intestine, with the excep- 

 tion of the rectum, which was slightly enlarged. There was no ccecum, Meckel's 

 diverticulum, or any appendices epiploicse. 



RESPIRATORY SYSTEM. 



Two points in the natural history of Weddell's Seal direct attention to the 

 morphology of the organs of respiration. The one, common to all marine mammals, is 

 the prevention of the passage of water into the lungs ; the other, the production of 

 sound. 



Dr. Wilson (loc. cit.) describes the voice as commencing " with a long and musical 

 moan at a high pitch, which gradually got lower, and sounded much like the ice-moans 

 that are common on an extensive sheet of ice. This was followed by a series of 

 grunts and gurgles, and a string of plaintive piping notes, which ended up exactly 

 on the call-note of a bullfinch. Then came a long shrill whistle, and a snort to finish, 

 as though he had for too long held his breath." 



In all the specimens in the collection the external nares were situated at the 

 anterior end of the snout and not on the dorsal surface, the position they assume in 

 the adult. At first they are in the form of small horizontal slit-like apertures 

 without any valvular apparatus. In the largest foetus the slits are crescentic, the 

 convexity being turned towards the median line of the nose ; they are almost vertical 

 in direction. The openings are guarded by valves formed by a prolongation inwards 

 of a fold of skin from the outer margin of the meatus. This flap when pressed down 

 completely occludes the orifice. Closure of the valve is effected by the lower fibres 

 of the pyramidalis nasi muscle, which on reaching the nose curve outwards and pass 

 into the substance of the valvular lid. Below the nares, these muscular fibres bend 

 inwards towards the middle line, some to be inserted into the premaxillary bone, 

 others to mingle with the fibres of the levator labii superioris muscle, and appearing 

 ultimately to interdigitate with the fibres of the pyramidalis of the opposite side. 

 Thus, the two muscles acting in conjunction form a kind of sphincter for both nostrils 

 and effectually close the valves. The nostrils lead into two large nasal cavities (/. n. c.), 

 one on each side, which are separated by a median cartilaginous septum (figs. 13, 14). 

 Springing from the outer wall of each chamber is a delicate scroll-like turbinal. From 

 the posterior part of the floor of each lateral chamber is an opening leading into an elon- 

 gated median chamber (TO. c.) which overlies the posterior part of the palate. The glottis 

 opens into the floor of this median chamber at its back part, the anterior surface of 



