502 Proceedings of the Royal Irish Academy/ 



bones in the tendons of the flexors, are observable on the plantar 

 aspect of these two metacarpals. 



Tendons. — Those of the long flexors are to be seen. 



Muscles. — Interossei occupying the same positions as in the previous 

 section. Pour lumbricales are also present, situated near the tendons 

 of the flexor longus digitorum. 



Mantis. — Sections passing through the distal extremity of the 

 manus present a very close resemblance to those taken from the pes. 

 The tendons of the perforating and perforated muscles lie in the same 

 position in both. 



A section taken through the first phalangeal joint shows the 

 cartilages, which, by subsequent ossification, become sesamoid bones 

 in the flexor tendons. 



The most instructive section of the manus is one taken through 

 the centre of the metacarpus. Such a section presents the following 

 objects for observation : — 



Bones. — There is no space left between the third and fourth 

 metacarpals, but a small one between the second and third and first 

 and second, and for the most between the fourth and fifth. The 

 three central metacarpals are of a somewhat oval shape. The fifth is 

 more nearly circular, while the first is of this shape (") . 



Tendons. — The slips attaching the extensor tendons to the bones 

 are visible, as are also the tendons of the perforating and perforated 

 flexors. 



Muscles. — The following are observable : — Flexor brevis pollicis, 

 flexor brevis minimi digiti. Three lumbricales. The normal inter- 

 ossei are present, but there is an extra interosseous muscle in the 

 interspace between the second and third metacarpal bones. This also 

 differs from the others in its situation, the normal muscles lying to 

 the palmar aspect of the metacarpals, and the extra one between the 

 two before mentioned. It is interesting, as pointing to a possible 

 original symmetry of the interossei in point of numbers ; but before 

 laying any stress on this point, I am anxious to discover whether a 

 similar arrangement obtains in other canine manus. 



I hope soon to be in a position to lay before the Academy a more 

 extended Eeport of my investigations on the human manus, which I 

 am now carrying on. 



Having lately obtained a large supply of materials, in the shape of 

 human foetus, I hope to be able to make a tolerably complete exami- 

 nation of them. 



In conclusion, I desire to take this opportunity of thanking 

 Dr. Macalister for materials and much kind assistance. 



i 



