212 



MR. J. B. SUTTON ON DISEASES OF 



[Apr. 20, 



contiguous margins ; the remaining digits were normal." I re- 

 member examining the specimen, at the time Mr. Forbes noticed it, 

 in the Prosector's room, and was impressed with the perfect sym- 

 metry of the malformation. 



Since then one other example of malformation in the manns of a 

 Monkey has occurred. A Gibbon ( Hijlobates leuciscus), which lived 

 in the Gardens a few months, was found to have a supernumerary 

 finger on each hand. In this case the additional fingers possess a 

 metacarpal bone which was attached to the ulnar side of the meta- 

 carpal of the fifth digit, and it seems as tiiough the supernumerary 

 bone was formed as a result of bifurcation of the distal end of the 

 fifth one. The carpal bones do not present any abnormality. So 

 few examples of polydactyly in Quadrumana have been noticed that 

 the case before us is worthy of lecord. 



Fig. 5. 



A follicular cyst from a Pielieusile-tail Porcupine, Sphingtmis prehensilis. 

 The upper figure represents the jaw after the removal of the cjst. 



w, the inferior dental nerve. The lower drawing is the cyst with the (eeth 

 projecting into it. The arrow marks the position of the mental foramen. 



As an additional illustration of symmetry in disease, the following 

 case is of value. A Prehensile- tailed Porcupine died from the 

 effects of a large abscess on each side of the mouth. These had 

 burst externally, giving rise to deep sinuses. A probe passed into 

 each gave evidence of necrosed bone ; and at first sight the case 

 seemed to be one of alveolar abscess consequent upon diseased teeth, 

 a condition of things exceedingly common in animals. On examining 

 the mouth I failed to find the lower incisors; this was very sin- 

 gular, because the bone at the symphysis was quite normal. On 

 tracing one of the sinuses by dissection, it was found to lead into 

 the mental foramen, and thence into a cavity occupying the body of 



