“hh: 
CETACEA—LILLIE. 97 
each hair which projected beyond the surface of the tubercle was about 10 mm. 
Some of the hairs situated at the tip of the snout, and which were without 
tubercles, only had 5 mm. of their length projecting from the surface of the skin. 
The height of the tubercles varied from half an inch to two inches. 
These hairs have been shown to possess a sensitive function,* and in all 
probability they serve to indicate to Whalebone Whales the presence of the small 
plankton animals upon which these whales feed. The sensitive feeler, or barbell, 
which occurs beneath the chin of certain fishes, which feed upon plankton, has 
probably a similar function to that of the vibrissae in the Mystacoceti. 
JACOBSON’S ORGAN. 
The remains of the ventral ends of Stenson’s duct could be seen in several 
specimens. They consisted of two shallow depressions on the ventral surface of the 
tip of the snout, very similar to those of Balaenoptera musculus, Linn.t 
THROAT-GROOVES. 
About twenty-four furrows were counted between the pectoral fins in several 
individuals, and they were found to agree in number and character with those of 
Northern members of this species.{ 
The pink coloration which was noticed by the present writer,§ a few years 
ago, in the throat-grooves of two species of Lalaenoptera was also observed in some 
of the New Zealand Humpbacks. Careful investigation showed that it was caused 
by an effusion of blood, which evidently takes place after the death of the animal, 
as pointed out by Mr. Burfield.j| There is, therefore, no truth in the surmise that 
the grooves may serve to aerate the blood. 
Their function is to give elasticity to the floor of the mouth, for the purpose 
of increasing the capacity of the mouth-cavity. Since the grooves extend backwards 
to the navel, it would seem possible that they also serve to increase the power of 
expansion of the lungs. On account of the reduced condition of the sternum and 
the mobility of the ribs, the dilatation of the thorax takes place laterally, and 
would be greatly facilitated by the extra elasticity imparted to its ventral wall by 
the furrows. It was of interest to note that the large superficial muscles, which 
* Japha, A., 1904, Zool. Jahrbiicher Abt. f. Anat. und Ont., Bd. XXIV., pp. 1-40. Rawitz, B., 
Tnternat. Monatschrift f. Anat. und Physiol., 1906, Bd. XXIII., Hefte 1-3. 
{ Kiukenthal, W., “ Vergl-anatom. u. Entwick. Unt. an Walthiere,” in Denkschr. med. naturw. 
Gesellsch. Jena, Bd. III, Theil 2, 1893, pp. 321, 349. Lillie, D. G., Proc. Zool. Soc., 1910, 2, p. 774. 
Burfield, 8. T., Report on Belmullet Station, British Ass. Rep., Dundee, 1912, p. 177. 
{ True, F. W., ‘‘ Whalebone Whales of the Western North Atlantic,’ Smithsonian Contributions to 
Knowledge, 1904, Vol. XXXIII., p. 224. Struthers, J., Journ. Anat. and Physiol., 1888, Vol. XXII, 
p- 118. 
§ Lillie, D. G., Proc. Zool. Soc., 1910, 2, p. 784. 
|| Burfield, 8. T., Report on Belmullet Station, British Ass. Rep., Dundee, 1912, p. 176. 
