52 The American Naturalist. [January A 
they sought to associate the reduction of the epiphyses with adaptation 
to an aquatic existence. 
“In dealing with the limb-skeleton they described a longitudinal 
cleavage of the phalanges, akin to that recorded by Kükenthal for the 
Cetacea. The only structures observed which were at all comparable 
to sup y phalanges derivations of the terminal (ungual) 
ones, arising proximally; and the observations lend no support to 
Kiikenthal’s view that supernumerary phalanges are epiphysial in 
origin. : 
“ The first upper incisor and the four lower ones of either side were 
shown to have milk predecessors, which are early absorbed. Five 
teeth were shown to be present on either side of the symphysial region 
of each mandibular ramus of Manatus, the fifth one being claimed as 
a canine; and in this animal the authors described milk predecessors 
to the two anterior pairs of mandibular cheek teeth.” 
On the Cephalo-humeral Muscle and the So-Called Clav- 
icle of Carnivora.—At a meeting of the Philadelphia Academy, 
Dr. Harrison Allen spoke of the peculiarities of the cephalo-humeral 
muscle in mammals and invited especial attention to the presence of a 
small fibro-cartilaginous disc in the junction of the cephalo-humeral 
with the muscles which are inserted in the bones at the region of the: 
shoulder. This is well defined in Felis and is identified as a rudimen- 
tal clavicle. Dr. Allen has detected this structure in Herpestes, Taz- 
idea, Cercoleptes, Bassaris, and Procyon. 
The cartilage is either in the form of a flat dise or a minute scythe 
shaped rod, and is constant in lying directly over the greatest convexity 
formed by the round of the shoulder. It seems to give strength to the 
center of a muscle system of which the cephalic, cervical, pectoral and 
latissimal sheets are parts. The identification of such a plate or rod 
with a true clavicle is doubtful, since in Balantiopteryx (a genus of 
bats) the structure above described is remarkably developed, while the 
clavicle is as well formed as in any other animal. ‘Phe long rod-like 
body is continuous with a fascicle of fibres arising from the pectoralis 
and receives the insertion of the occipito-pollicalis. The anterior end 
of the rod lies in the upper border of the wing membrane and is con- 
tinuous with the fibrous thread which represents the tendon of the 
occipito-pollicalis as this muscle is defined in the bats generally. From 
both the proximal and distal divisions of this muscle delicate fascicles 4 
pass toward the elbow and the entire plan appears to be associated 
with the rudiment of the characteristic skin sac. Slight modification — 
_ of this arrangement is met with in the allied genus Rhynchonycteris. 
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