280 PROF, ST.-GEORGE MIVART ON THE [Feb. 21, 



The female sexual organs have been described by Hunter ; see his 

 ' Essays and Observations,' vol. ii. p. 223. 



The brain presents a much less decidedly quadrate form than that 

 of the Porcupine (most probably i7y«^re,«- cris^a^a)]figured by Leuret '; 

 and it is even more smooth, there being but a single short and slight 

 depression (or rudimentary sulcus) at the hinder end of the most 

 anterior third of the dorsum of each cerebral hemisphere. The 

 pituitary body is very large, and the corpora trapezoidea well deve- 

 loped. - 



The bracJdal plexus^ is formed by the sixth, seventh, and eighth 

 cervical nerves together with the first dorsal. 



The main part of the eighth cervical, having received a branch 

 from the seventh cervical and another from the first dorsal, is 

 continued as the median nerve, a smaller branch from the same 

 junction constituting the uhua- nerve. The mtisculo-spiral nerve is 

 formed by the smaller branch of the eighth cervical uniting with a 

 portion of the seventh cervical. The circumflex nerve arises by two 

 roots — one a branch of the sixth, and the other of the seventh, cervical 

 nerves. The external cutaneous nerve is formed mainly by a branch 

 of the sixth cervical ; but it receives a small filament from the root 

 of the circumflex nerve just after the latter has been formed, as above 

 stated. The internal cutaneous springs from a branch of the first 

 dorsal, which receives a branch from the seventh cervical root of the 

 median nerve. 



The lumbosacral plexus is composed of the last four lumbar and 

 the first two sacral nerves. It is very simple, with little interlace- 

 ment. The anterior crural nerve is formed by the first two of the 

 six, from the junction of which the obturator nerve is also given off. 

 The great sciatic nerve is formed by the last two lumbar nerves only ; 

 while the small sciatic nerve springs from the junction of the two 

 sacral nerves. 



LlMB-MuSCLES OF ErETHIZON. 



Muscles of the Fore Limb. 



Panniculus carnosus. — The dorsal portion of this muscle is inserted 

 into the pectoral limbs partly over the spine of the scapula by 

 attachment to the fascia investing the supraspinatus, and partly 

 into the outer surface of the humerus (between the deltoid and the 

 outer part of the triceps) down to the apex of its deltoid crest. The 

 abdominal portion of the same muscle is inserted into the humerus 

 outside the greater tuberosity and inside the upper part of the 

 deltoid crest. 



The pectoralis is so united with the ventral part of the panniculus 

 that they seem like two parts of one muscle. The true pectoralis, 

 however, arises from the sternum, and is inserted into the distal 



' See plate iii. of Leuret and Gratiolet's ' Anat. Comp. du Systeme Nerveux.' 

 The brachial and himbo- sacral plexuses were dissected out for me by Mr. 

 W. Pearson ; and the drawings aj-e from his dissections. 



