112 



with this the so-called ascending ramus of the lower jaw-bone has inclined 

 downward into a supine position so as to become a prolongation of the 

 anterior part of the bone. This increase of the capacity of the lower jaw in 

 the interest of a greater absorption of food has led at the same time to a 

 considerable removal of the posterior articulation process from the temporat 

 bone, from which it follows that there can be no question of an articulation 

 proper. Hence has arisen a position of the inferior maxilla entirely disconnected 

 from the skull, which appears very singular at first sight because it is in such 

 startling contrast with what is observed in the skulls of all other mammalia. 

 A few more data may however be acceptable to clear up the question under 

 consideration. 



When on Jan. 8th 1917 I saw the whale washed up by the ocean, the 

 body already in a state of decomposition was on its back, the upturned 

 inferior mandibles no longer occupying their natural position having been 

 pushed aside by the native population for the purpose of wrenching loose the 

 numerous baleen-laminae from the cuther rim of the upper maxilla. It was 

 indeed still visible that the lower jaw protruded in front of the upper one, 

 but how far was no longer to be measured with accuracy. 



The protrusion of lower jaw before the upper one is however discernible 

 m Balacnoptera musculus L. in True (6) plate 13 fig. 3, plate 15 fig. 1 and 2, 

 and plate 48 fig. 2; and for Balacnoptera physalus L. in True (6) plate 10 fig. 

 1, 2 and 3, plate 12 fig. 1, 3 and 4, and plate 37 fig. 3. Further in Flower: Proc. 

 Zool. Soc. London 1869, plate XLVII fig. 1 for Physalus antiqiioriim = 

 Balaenoptera physalus L.; whilst the protrusion of the lower jaw has also been 

 'made allowance for in setting up the skeleton of Megaptcra nodosa Bntr. repro- 

 duced in True (6) plate 36 fig. 1. 



In conclusion it may be mentioned that according to True's account (6) p. 

 116 the length of the protruding section is 2,1% of the total length in Balaenop- 

 tera physalus L., which applied to our Balaenoptera would work out to 2.1 % X 

 2728 c.M.=57.3 c.M.. Flower (Proc. 1869) states for this in Balaenoptera phy- 

 salus L. nearly 21/2 %, which in our case would yield 21/2 %X2728 c.M. = 68.2 

 c.M. In the skeleton now set up at Buitenzorg the lower jaw only protrudes 52 

 c.M. before the upper one. How far the thickness of the skin and flesh on the 

 upper and the nether iaw may be a factor in this question is here left out of 

 recount. In this positirn of the inferior maxilla the processus coronoideus is 

 situated more forward than the eve. In connection, with this the fle<^hy lower 



