198 THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



amounting in actual measurement to about T 6 ^ of an inch ; (2) a slight excess in 

 the height of the occiput, amounting to -fa of an inch ; (3) a decrease in the breadth 

 of the beak at the middle. These can scarcely be regarded as having any consider- 

 able importance. 



In comparing the young individuals of which Sir Wm. Turner has given meas- 

 urements with the adult, it is interesting to observe that the beak increases decidedly 

 in relative length in the latter, causing all the dimensions which include the beak 

 to show an increased proportion to the total length. The same is true also of the 

 width of the skull across the squamosals and the orbital plates of the frontals, and 

 the length of the mandible. On account of these changes in proportions incident 

 upon growth, it is necessary to compare skulls of the same age, adults with 

 adults, and immature specimens with immature specimens, to arrive at correct 

 conclusions. 



For comparison of details of structure I have had the use of the skull from 

 Norway in the U. S. National Museum (No. 13877), and such figures as are found 

 in the literature. The Massachusetts skull and the Norwegian one are figured on 

 pis. 22, 24, and 26. The former is from a much younger individual than the 

 latter. 



On comparing the figures it will be seen that in general the correspondence is 

 very close, but that in a number of details the two skulls exhibit differences. For 

 example, the nasals are longer and narrower in the American skull than in the 

 Norwegian, the proximal ends of the nasal processes of the maxillae are narrower, 

 and the anterior margin of the supra-occipital is more rounded. To determine 

 whether these and other minor differences are of importance, it is necessary, of 

 course, to make further comparison with other skulls. This I am only able to do 

 through the figures hitherto published by various cetologists. 



So far as I am aware, no adequate figure of the skull of the European B. 

 acuto-rostrata has been published hitherto. The drawings of the lateral surface 

 and of one half the superior surface, reproduced by Capellini (12, pi. 1, fig. 1 ; pi. 

 2, fig. 1) are on the whole the most satisfactory. Eschricht's figures (57, pi. 9) are 

 excellent, but appear to be out of proportion in the posterior part, especially 

 as regards the tympanics and nasals. Extended descriptions have been pub- 

 lished by Carte and Macalister (14), Capelliui (12), and Van Beneden and 

 Gervais (8). 



The Massachusetts skull agrees very closely with Capellini's figures, as will be 

 seen by comparison of plates 22, 24, and 26. The descriptions also appear to agree 

 well, as far as I have been able to interpret them. In one particular, however, Carte 

 and Macalister's account is not in accord. They state that the malar bone is broader 

 behind than in front and that " its wider or posterior extremity was flattened and 

 fitted in between the anterior border of the gleuoid process of the squamous bone 

 and the posterior angular process of the frontal, where a digital depression existed 

 for the reception of the former" (14, 213). No such shape or articulation is to 

 be found in the Massachusetts skull, in which the anterior end of the malar is the 

 broader, and the posterior smaller end articulates, as would be expected, with the 



