DR. J. MURIE ON THE ORGANIZATION OF THE CAAING WHALE. 281 
distinctly marked in Glodiceps, Grampus, and the White-beaked Bottlenose and Rorqual. 
They undoubtedly resemble the interspinales superiores of these authors, but pass from 
one chevron hemo-spinal element to the adjoining. I prefer to designate them as 
interhemo-spinales, this term being more in accordance with morphological anatomy. 
Stannius likewise differentiates, and names as M. interaccessorii a number of tendino- 
fleshy fascicles which intervene between the one and the other accessory spinous processes 
of the lumbar and dorsal vertebra, in a longitudinal direction. These have not been 
observed by me; but I am inclined to regard them as intermetapophysales. 
3. Muscles acting on the Sterno-costal Framework.—The rectus abdominis in the 
“ Deductor” is striking on account of its vast thickness in the middle of the thoracic 
region. Springing by a strong aponeurotic tendon from the manubrium, becoming 
fleshy opposite the hinder border of the pectoral limb, it spreads out and covers a con- 
siderable share of the hinder surface of the chest. By degrees narrowing, it tapers 
and apparently ends near the generative aperture, though a portion is continued on 
towards the innominate bone, and by a tendon is fastened to the infracaudal fascia. 
The attachments of the rectus in the Porpoise are nearly similar. Stannius! notes a 
connexion with a tolerably strong aponeurosis, which proceeds from the pelvic region 
to the transverse process of the nineteenth lumbar vertebra and general caudal fascia 
investment. In the Piked Whale’ penniform insertions into the second to sixth ribs are 
recorded. In Risso’s Grampus* the muscular belly stops at the second rib, aponeurosis 
continuing to first rib and sternum; posteriorly it agrees with that of G. melas. 
The obliquus externus, internus, and transversalis are relatively weaker than the 
preceding, though each is a great fleshy sheet. The former is attached to all the ribs 
about their middle, save the three anterior ones, where the fibres spring near their 
sternal ends. ‘There are a few digitations with the serratus magnus; posteriorly the 
external oblique does not reach the pelvic bones. 
Both external and internal intercostals seem to possess considerable motor power 
over the ribs, judging from their full development. More particularly is this the case 
with the first external muscle, duly commented on by Stannius in the Porpoise. I also 
specially noted the presence of strong fleshy fibres corresponding to the triangularis 
sterni in G. melas (vide fig. 69) and L. albirostris. Under the head of musculi 
ossium sterni costalium, Stannius* describes bundles in the Porpoise which appear to 
me identical with the triangularis. The Rostock professor likewise alludes to a 
sterno-costalis® in the same animal. This double slip, with obliquely set fibres, has one 
part attached to the sternum and first rib and its cartilage, another between the first 
and second cost and sternal cartilages. 1 presume it agrees with what is now better 
known as the supracostal. Meckel® describes, but does not name, a muscle identical with 
the above in Cetacea, which he regards as assisting respiration in the diving animals. 
tricep. 19. * Phil. Trans. 1868, p. 224. ? Journ. of Anat. vol. v. p. 134. 
‘ L.c. p. 38. o Lr Ga Ne Oils ® L.c. p. 190. 
