ANATOMY OF MEGAPTERA LONGIMANA. 85 



the first is nearly semicircular (2| by 1^ inch) and very shal- 

 low ; I inch more in its long direction than that of the 7th 

 cervical and not so flat, and has, like the 7th cervical, a deep 

 pit behind. The 2nd, 3rd, and 4th are increasingly narrower 

 and much bent (the 3rd, length, outwards and forwards, 3 inches, 

 breadth, antero-posteriorly, under 1 inch) and much raised on 

 their oblique outer three-fourths, like the side of a trough. 

 The 5th is a deep ovoid fossa (2 inches by 1^) with a deep 

 non-articular pit (1 inch long) behind it. The 6th (2^ by 1|) 

 is a shallow mostly vertical surface with a smaller pit behind it. 

 The 7th becomes suddenly lost as an articular cavity, presenting 

 only a smooth apparently non-cartilaginous area bounded by 

 faint ridges. 



[In B. musculus, the 1st is a semi-elliptical surface (2| by under 

 1 inch) and more raised externally than in Megaptera ; the 2nd and 

 3rd are quite shallow semi-lunes ; the 5th, a shallow pointed ovoid 

 (2 1 inches by 1 inch), facing obliquely inward, with a pit behind ; 

 the 6th suddenly shows the first internal process, and, in front of 

 this, a flat vertical area without sub-cartilaginous appearance.] 



Surveying the series of the ordinary great anterior articular 

 processes, they are strikingly different in Megaptera and B. 

 musculus, especially in the dorsal region; rhomboid and directed 

 upwards and forwards in Megaptera, square-shaped in B. mus- 

 culus. In Megaptera, back to the 6th limibar, the concave 

 anterior border of the pedicle rises obliquely to the articular 

 process, meeting it at a rounded obtuse angle, and the anterior 

 border of the process is directed upwards and forwards. The 

 posterior border of the process is oblique, in the same direction. 

 The upper border is a little convex, about J inch thick and un- 

 finished. The unfinished edge turns down for J inch to 1 inch 

 round the anterior comer, not at all on the posterior corner, so 

 that any further ossification would increase the obliquity of the 

 processes. On the last four lumbar, the angle between the 

 anterior border of the pedicle and the process becomes rounded, 

 and, on and after the 1st caudal, is lost, so that the pedicle 

 and the process now form one interrupted concave anterior 

 border. This concave border becomes less and less oblique, is 

 vertical from the 5th to the 7th caudal, behind which the 

 articular processes are merely low convex ridges. On the last 



