176 



THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



BALMNOPTERA MUSCVLUS (L.). NEWFOUNDLAND. GIBTH. 



In Nos. 18, 9, 5, the girth at the tip of the pectorals, or the greatest girth, 

 would be, by calculation, 34 ft. 4 in., 36 ft. 4 in., and 34 ft., respectively. 



ABDOMINAL RIDGES AND FURROWS. 



The abdominal or thoracic ridges and furrows in this species, as in B.physcdus, 

 extend backward from the mandible to the navel, and between the pectoral fins and 

 eye extend upward nearly to the level of the latter. The ridges also anastomose 

 irregularly, and toward the posterior end many pairs unite, so that the total num- 

 ber here is much less than it is farther forward, and the breadth of each much greater. 

 The breadth of the larger ridges between the pectoral fins in the Newfoundland 

 Sulphurbottoms is about 2| inches. (PI. 14, figs. 4-6.) 



In number the ridges vary as in B. pliysalm, and the totals do not differ ma- 

 terially from those of that species. In different specimens of Newfoundland Sul- 

 phurbottoms the totals were as follows, and were obtained by counting from the 

 median line to the root of the pectoral and multiplying by two : 



BAL&NOPTERA MUSCULUS (L.). NEWFOUNDLAND. NUMBER OF ABDOMINAL RIDGES. 



The quite remarkable variation in number of ridges appears not to be corre- 

 lated with sex or size. 



