Paekeb.— Notes on Baleenoptera musculua ? 9 



narrower at their anterior ends. Judging from published figures also, the 

 upper surfaces of the bones seem to be unusually strongly ridged. Each 

 has a prominent ridge along its inner border, then a somewhat triangular 

 depression with forward apex, then a strong oblique ridge passing from 

 about the middle of the posterior border of the bone to its antero-internal 

 angle ; from the outer edge of this ridge the bone slopes downwards, end- 

 ing externally in a low ridge. 



2. The Jugals (fig. 3). — I have not succeeded in finding any special 

 description or figure of the jugal ; but, judging from the appearance of the 

 bone as shown in Van Beneden and Gervais's figures of the skull of 

 B. musculus* that of the present specimen appears to be broader at its 

 anterior and narrower at its posterior end, than usual, and to be somewhat 

 strongly curved. Owing to the absence of separate figures of this bone and 

 of the lacrymal (fig. 2), in the works at my disposal, I have thought it 

 advisable to give figures of both, drawn to the same scale as the nasals. 



3. Breadth of Beak. — The proportion of the breadth of the beak to the 

 length of the skull seems to be smaller than usual, being as 17 - 5 : 100. In 

 six skeletons measured by Flower, the proportion varies from 18 : 100 to 

 21 : 100. 



4. Vertebral Column. — The places at which the various dimensions of 

 the vertebras reach their maximum, differ slightly from those recorded by 

 Murie in the Bosherville Gardens specimen,! and the relative dimensions of 

 the vertebras themselves show certain differences, but I do not consider 

 these of sufficient importance to be recorded, except in the table of 

 measurements. 



5. The Sternum (fig. 4). — This differs from the corresponding bone in 

 all the skeletons of B. musculus of which I have seen descriptions, in 

 being longer than broad, like that of B. rostrata. The length is to the 

 breadth as 16 : 13, while, in other specimens measured, the proportion is 

 about 16 : 20. The antero -lateral edges and the lateral angles were, how- 

 ever, evidently edged with cartilage, so that the breadth was probably 

 considerably greater in the fresh state. 



Van Beneden and Gervais give the excess of breadth over length in B. 

 musculus as a character of specific importance. Von Haast also figures the 

 sternum of B. australis, which he seems to think is probably identical with 

 B. musculus, as broader than long,:|: and the same is the case with a speci- 

 men of the same species described by Hector. || 



* Op. tit., pi. xii. and xiii., figs. 11 and 12. t P.Z.S., 1865, p. 206. 



I " Notes on a Skeleton of Bala.nopte.ra australis, etc.," Proc. Zool. Soc, 1883, p. 592, 



|| " Notes on New Zealand Whales," Traus. N.Z. Inst., vol. vii., 1874, p. 251. 



