WiNDLE — Preliminary Report on Muscular System. 501 



LXXI. PEELIMIaSTAET RePOET 0^- THE EmBETOLOGY OP THE MaMMALTAN" 



MuscTJiAK System. By B. C. A. "Wendle, B.A, 



[Eead, June 27, 1881.] 



The subject of the development of the muscular system is one which 

 has up to the present time received very little attention. The litera- 

 ture on the subject is extremely scanty, consisting only of a few 

 Papers by Georg Euge, of Heidelberg, and Cunningham, of Edin- 

 burgh. 



In carrying out the investigations, for which I received last year 

 a grant from the Eoyal Irish Academy, I have made a large number 

 of microscopic sections of the manus and pedes of several puppies 

 (foetal) of the tenth day. I have also made sections of the manus and 

 pedes of human embryoes of various ages. In this preliminary 

 Eeport I purpose giving a short description of the condition observed 

 in the manus and pes of the foetal puppy of ten days. 



Pes. — Commencing at the distal extremity, the tendons of the 

 flexor brevis digitorum (perforatus) are seen attached to the three 

 central digits, and perforated by the tendons of the flexor longus 

 digitorum (perforans). The bones at this point of section are of a 

 somewhat rounded shape, flattened on their plantar aspect. 



Approaching nearer to the proximal extremity, the point of 

 section passes through the four digits, to which the same flexor 

 tendons are attached ; whilst two slips of tendon from the extensor 

 longus digitorum or brevis are to be observed on the dorsum of each 

 of the three outer toes. 



A section through the centre of the metacarpal bones presents the 

 following points for observation : — 



Bones. — There is much less space between the three middle meta- 

 carpal than between these and the first and fifth. The latter two 

 also are of a much more regularly circrdar shape than the others. 



Tendons. — On the dorsal aspect slips connecting the extensor 

 tendons with the bones. 



On the plantar aspect the tendons of the flexor longus digitorum. 



Muscles. — The interossei are all on the plantar aspect of the foot, 

 and are of the normal number and distribution. The fibres of the 

 flexor brevis digitorum are visible, cut transversely. The flexor 

 brevis h"llucis and flexor brevis minimi digiti are also to be seen. 



A section through the proximal extremities of the metacarpals 

 shows — 



Bones. — The three middle metatarsals are very close to one 

 another. The first and fifth are closer to the remaining ones than in 

 the previous section. The shape of the first and fifth, instead of 

 being round, is now spade-like, or, more strictly speaking, like the ace 

 of spades in shape. Cartilages, subsequently to ossify into sesamoid 



