ANATOMY OF MEGAPTERA LONGIMANA. 91 



[In B. musculus, as the posterior articular processes would pass, in 

 extension, internal to the lesser anterior processes, the latter main- 

 tain their usual position as the true anterior articular processes. 

 Whether they are serial with the outer or inner margin of the 

 articular surfaces on the anterior dorsal vertebrae does not affect 

 their homology, as they are to be regarded as these processes some- 

 what rotated, so that the sides of the zygantrum are more vertical.] 



TRANSVERSE PROCESSES. 



18. GENERAL REMARKS ON THE TRANSVERSE PROCESSES IN 

 GET ACE A. The dorsal transverse processes vary much in the 

 Cetacea, in their place of origin ; in direction, antero-posteriorly 

 or vertically ; in form ; in length, breadth, and thickness, and in 

 the form of their costal facets. Dorso-lumbar transverse pro- 

 cesses have generally a forward direction, except some of the 

 posterior dorsal which have a backward direction. This may be 

 said of Mammalia generally, but the greater length of the 

 posterior dorsal transverse processes in Cetacea renders it more 

 evident in them. This is very clearly seen in the toothed 

 Cetacea, e.g., Globicephalus and Phocena communis. The greatly 

 forward direction of the anterior dorsal transverse processes 

 enables the head of the doubly-attached rib to reach the body 

 of the vertebra in front. The more posterior of the ribs have 

 only the costo-transverse articulation, are a-sternal, and have a 

 greater slope downwards and backwards than the anterior, and 

 the transverse processes which support these ribs are directed 

 backwards. The lumbar processes, generally after the first, 

 again assume the forward direction. In the Balseriopterae, the 

 neck and head of the anterior ribs are represented by a ligament, 

 and the very greatly forward slope of the anterior dorsal trans- 

 verse processes builds up posteriorly the great lateral pyramid 

 formed by them and the cervical transverse processes. There 

 is, in them, the same backward direction of the posterior dorsal 

 transverse processes where the ribs become smaller ; the lumbar, 

 again, after the first, assuming the forward direction. 



A typical dorsal transverse process may be divided into two 

 stages, which may be termed the neck and the wing, seen best 

 in Balasnoptera musculus. Both borders are at first concave 

 where they join the body. The stages are strongly-marked on 

 the anterior border, where an angle is formed about the middle 



