22 



The body has the elegant spindle shape characteristic of tlie species, with the greatest thickness in front of the 

 navel, between the dorsal fin and the pectorals. In the fætuses from 75 to 84 centim. in length, a slight sinking of the 

 outline of the body behind the head is apparent, but this may possibly be due to the preserving process. It does not 

 appear in the 9o centim. long foetus. The pectoral fins, which are situated very low down, at the junction of the flanks 

 with the abdominal surface, are 1.5.5 niillim. long in the 84 centim. long iVetus, and amount to \/5.4 of the length of tlie 

 body. Their convex ventral margin and concave dorsal margin with the angular convexity in its inmost tliird part, arc of 

 tlie same cliaracter as in the full-grown animal. 



The umbilicus is under the middle of the dorsal tin. The penis is not withdrawn into any fold of skin, hut 

 lies with the preputium right out. Half way between the glans and the anus, at the base of the prominence of the genital 

 region, there are 2 clefts, each about 2 niillim. in length, lying side by side, which are the rudimentary mamnue. 



The postanal portion is very much compressed and higli, with a pronounced dorsal and ventral comb in the 

 jiart lying immediately in front of the tail. The tail is deeply cleft, and the iiighly developed tail-lobes stretch out their 

 points far beyond the cleft (fig. 2, p. 22). 



Distribution of colour. The black or blue-black colour is distributed over the whole of the dorsal surface of 

 the body, and, in the tail region, over the ventral suriace also, extending forwards almost up to the anus: the pectorals are 

 also black. The surface of the abdomen, on the other hand, is light or whitish. The upper jaw is also of a dark colour, 

 with the exception of the lighter margin of the upper lip. The lower jaw, like the abdominal surface, is whitish. Three 

 belts of colour may thus be distinguished on the body, viz. the almost black dorsal colour, the greyish colour of the 

 sides, and the wliitisli colour of the abdomen. The greyish zone begins on the upper jaw above tlie eyes, and 



Fig 2. 



The tailfin of the 842 inillini. loii"-. fætiis of LaKeiiorli vii cliu < acutus. seen from above. 



includes the greater part of the side surfaces riglit out to the tail fin, (with a ratlier lighter tinge in the neck and chest 

 region) descending farthest at the navel and genitali:i. The boundary above is a convex curve running to the back of the 

 anus. The dorsolateral patch cliaracteristic of the species "acutus", which commences beneath the dorsal fin, is now 

 already divided into one anterior, long, oval, lighter, lower part, and one posterior, band-like part, of a greyish shade, 

 running forwards like a narrow band by the side of the white. — Among other peculiarities of colouring may be noticed a 

 black streak, uniting the dark part of the upper lip with the darkly coloured eye region, thus imparting the appearance of 

 : pectacles, and a blackish-grey streak from the eye region to the pectorals (Fig. 1 in the li'tterpress, j). 21). 



General remarks. Although we cannot, unfortunately, draw any decided conclusions from the deformed 8 inilliiii. 

 long embryo as regards the outward form, yet the relatively enormous length of the tail seems to be a characteristic feature 

 of ([uite small embryos of the Cetacea. This must be put down as a peculiarity which must be taken into account if an 

 opinion is to be formed of the phylogeny of these animals. 



The little embryos from 2'/, to 3 centim. in length have already a few of the characters of the Cetacean 

 type mingled with the ordinary mammal-like features, and the Odontocete type is recognisable before the embryo has 

 attained to Vio of the size of the new-born animal. When the tW'tus has attained to 'A of its full length, the generic 

 characters begin to appear; and when it is half-grown as regards its length, the specific characters already assert themselves. 



