112 



BAIiJENOPTEETD^J. 



Cuvier (Oss. Fos. v.) determined by the form of the head three 

 kinds of Tinner Whale, but he was doubtful if they might not be 

 varieties of age of the same species. These kinds are the types of 

 three genera : viz. Rorqual du Cap = Megaptera, Eorqiial de la 

 Mediterranee = Physalus, Rorqual du Nord = Sibbaldius. 



" In the first three columns of the following Table are given the 

 actual length of the cranium, greatest breadth (at the squamosals 

 behind the orbit), and breadth across the middle of the beak, in 

 inches; and in the last two, the proportionate breadth of the skull 

 and beak to the total length, the latter being reckoned at 100. 



Length 



Breadth 



of 

 cranium. 



Breadth 



of 



beak. 



Proportion to ■ 

 length. 



Breadth 

 of 



BknU, 



Breadth 



of 

 beak. 



Adult. Antwerp 



Adult. Iiouvaiu , 



Adult. Alexandra Park 



Adult. Kosherville Gardens 



Young. Leydeu f. 



Young. Mu8. E. Coll. Surg 



Cuvieriua latirostris. 



TTtreoht (Mus. Lidth de Jeude) . . . 

 Sihbaldius borealis. 



Adult. Ostend. (Approximation "1 

 from Dubar's measurements.). . J 

 Sibbaldius laMceps. 



Adolescent. From Java, in Ley- "1 

 den Mus J 



Young. Ijeyden 



Sibbaldius Schlegelii. 



Young. Brussels 



Young. Berlin. (Approximation ] 



from Eudolphi's figure.) / 



Balcsnoptera rostrata. 



Adolescent. Brussels 



Adolescent. Mus. E. Co: 1. Surg.... 



Young. Mus. E. Coll. Surg 



184 

 179 

 186 

 168 

 126 

 111 



118 

 256 



116 

 79 



80 



78 



63 

 65 



48 



78 

 86 

 75 

 60 

 56 



60 

 118 



57 

 40 



38 

 36 



34 

 35 

 24 



33 



32 



36 



34i 



2? 



22i 



32 



22 

 16 



15 

 18 



13 

 15 



52 

 44 

 46 

 45 

 48 

 60 



51 

 46 



49 

 51 



48 

 46 



54 

 54 

 50 



18 

 18 

 19 

 20 

 21 

 20 



27 



19 

 20 



19 

 22 



21 

 23 

 20 



" It is seen by this that the individual differences among specimens 

 oi Physalus and Sibbaldius are considerable, the proportionate breadth 

 of skuU ranging in the first case between 44 and 52, and of the beak 

 between 18 and 21, and in the second genus between 46 and 51, 

 and 19 and 22 ; and these differences do not seem at all to be regu- 

 lated by age. A shght allowance must certainly be made for errors 

 arising from the difficulty of measuring straight lines with exactness, 

 especially single-handed, upon these large irregular objects. On the 

 whole, however, the specimens ot Sihbaldius have no advantage on 

 the score of breadth. The examples of Balcenoptera rostrata are 

 slightly broader than the others in proportion to their length. 



" Van Beneden is of opiaion that this specimen, as well as that at 

 Berlin, is referable to the same species as the very large female 

 Whale taken near Ostend in 1827, the skeleton of which was exhi- 



