518 
Proceedings of the Royal Irish Academy. 
The incidental allusions to Meckel's* dissection of the Ai are taken from 
Professor Macalister's paper. The weights of the principal muscles, 
which are given in decimals of an ounce, afford an easy means of com- 
parison : — 
In the head : — 
Masseter arises from the anterior and posterior surfaces of the de- 
Bcending jugal process and runs backwards to the usual mandibular 
insertion. The internal pterygoid is large, but there is no external 
pterygoid. 
The following points of general anatomy are worthy of notice : the 
parotid gland is well developed and lobulated, the sublingual and sub- 
maxillary are absent ; the tongue is devoid of a cartilaginous septum ; the 
oesophagus lies well to the left of the trachea, which is coiled up in an 
S curve on the left lung, which is decidedly the larger of the two ; 
there is the usual rete mirabile in the axilla, and a very large one in the 
course of the femoral artery. 
In the fore limb : — 
Trapezius arises from the spines of the lower five cervical vertebrae 
and from those of the upper five dorsal; it is inserted into the scapular 
spine for half its length, into the coracoid and acromion processes, and 
into the rudimentary clavicle ; it was not divisible into parts. Pro- 
fessor Macalister found the origin from all the cervicals except the atlas, 
and from the six upper dorsals, but there was no clavicular insertion; 
however, this is described by both Professors Humphry and Meckel, 
the former remarking that the cervical portion is scarcely traceable to 
the skull, and that its hindmost fibres are continued into those of the 
deltoid. 
Rhomboid is ('OS) a small muscle arising from the eighth and ninth 
cervical, and four upper dorsal spines, and inserted in the usual way. 
There was no occipital prolongation either in our specimen or in B. 
tridactylus, but the origin in the latter was more limited, only extending 
from the last cervical to the third upper dorsal. 
Trachelo-acromial is absent in all. 
Serratus magnus ('02) had no distinct levator scapulae portion, 
either in our specimen or in Professor Macalister's ; that part of the 
muscle corresponding in position to levator scapulae arises from the 
transverse processes of the seventh, eighth, and ninth cervicals, and is 
inserted into the usual place. Professor Humphry says that the 
levator scapulae is distinct from the serratus, arising from the sixth, 
seventh, eighth, and ninth cervical transverse processes, and inserted 
* System der Vergleichenden Anatomie, 1828. Meckel's specimen seems to have 
been Arctopithecus Blainvillei, since it agrees almost exactly with our individual whilst 
differing considerably from Bradypus tridactylus. The animal described above was sent 
over here by the Rev. J. M'G.Ward, Chaplain to H. M. S. Egmont, from Rio de Janeiro, 
under the care of Dr. Armstrong, being intended for the Royal Zoological Society's 
Gardens. It died, however, shortly after its arrival in Dublin, and was given by Dr. 
Armstrong to Dr. Macalister for dissection. 
