ANATOMY OF MEGAPTERA LONGIMANA. 55 



inches; in the 64-feet-long B. musculus, 14| inches and 11 

 inches ; while in this Megaptera the beak is 5 to 5i, the body 

 6| inches. 



The Superficial Inteiyelvic and Interfemoral Aponeurosis. 

 — This great sheet of fibrous tissue is seen (fig. 15, k.lc.) to pass 

 across superficially between the pelvic bones and neighbouring 

 parts, connecting them together, and supporting the parts of 

 the penis. Breadth, antero-posteriorly, fully 12 inches, extend- 

 ing forwards in front of the pelvis to the transverse superficial 

 muscle which exists there, and backwards to the beginning of 

 the posterior third of the pelvic bone. Here it ends rapidly in 

 a curved line with a median peak. If this edge is not natural 

 the membrane is at least very thin from here back to the levator 

 ani muscle, this space appearing after dissection as a perineal 

 ^vindow through which the parts at the root of the penis are 

 seen. This interpelvic aponeurosis may be regarded as a part 

 of the general transverse aponeurosis of the region, specially 

 thickened and attached where it lies between the pelvic bones 

 and thigh bones. Thickness at the middle line, about \ inch, 

 the part opposite the femur and fore part of the pelvic 

 bone, J inch. Its lateral connections at the pelvis are in three 

 strata ; the deepest attached to the pelvic bone ; the middle, 

 passing through between the pelvic bone and the femur, and 

 blending with the deep tendinous tissue prolonged from the 

 caudal mass ; the superficial stratum, attached to the inner 

 edge and superficial aspect of the femur, blending with its 

 perichondrium. Behind the femur the aponeurosis joins the 

 posterior fibrous connections of that bone ; anteriorly it passes 

 on the deep aspect of the anterior fibrous connections of the 

 femur, to reach the inner edge of the anterior third of that bone 

 and the deep longitudinal tendinous tissue, but it is not attached 

 to the very apex of the femur or to the prolongation band, going 

 across above these, and leaving them as more superficial parts. 

 This great aponeurosis is composed of coarse transverse bundles 

 of white fibrous tissue mixed with areolar tissue and fat. It 

 was only after repeated examination with the microscope that I 

 was satisfied it was nowhere muscular. In dissecting not very 

 fresh cetacean tissues, streaks of brown-coloured blubber are 

 sometimes extremely like muscle to the naked eye. 



