508 PROCEEDINGS OF SECTION D. 



10.— THE ANATOMICAL VARIATIONS PRESENTED BY 

 A CASE OF A THORACOPAGOUS LAMB MONSTER, 

 TOGETHER WITH AN ACCOUNT OF THE DEVELOP- 

 MENTAL EXPLANATION OF THE SAME. 



By RICHARD J. A. BERRY, M.D., Edin. ; M.D., Melb. ; F.R.G.S., Edin. ; 

 F.R.8., Edin. ; Professor of Human Anatomy in the University of Melbourne. 



SYNOPSIS. 



Rarity of condition and occurrence in man. 



Description of present specimen. 



Dissection of same, with special reference to tlie alimentary and 

 and circulatory systems. 



Origin of double terata. Older theories, modern views, and author's 

 theory. 



Embryological errors responsible for production of present mon- 

 strosity. 



Introduction. — Some few years ago Professor Berry was fortunate 

 enough to have presented to him by Dr. F. W. N. Haultain, of Edinburgh, 

 two cases of thoracopagous monsters, which were carefully dissected 

 and fully described in the " Transactions of the Edinburgh Obstetrical 

 Society " and also in the " British Journal of Obstetrics."(l) More 

 recently, Professor Berry was equally fortunate in having presented 

 to him by Mr. A. J. Beattie, a medical student of the University of 

 Edinburgh, a similar monstrosity occurring in a lamb. The dissection 

 of this last case was undertaken for Professor Berry by Dr. J. D. Sinclair. 



Description. — -The present example is a thoracopagous lamb 

 monster, both the twins being full-term females, and of the subtype 

 known as sternopagous tetrabrachius — that is to say, each twin has 

 two upper limbs, and the internal organs — more particularly the heart — 

 show various degrees of fusion. The present specimen came from a 

 large sheepfarm at Luib, in Perthshire, Scotland, and, if the shepherd 

 is to be believed, its rarity is shown by his statement that it is the first 

 example of the kind which he has met with in an experience of 40 yearrf, 

 with an average of 1,000 lambs per annum. 



External Appearances. — The line of fusion extends from the upper 

 part of the thorax opposite the fore limbs to the umbilicus. Both 

 upper and lower limbs are perfectly free, and are consequently eight in 

 number. The twin on the right measures, on the dorsal surface, from 

 the tip of the nose to the tip of the tail, 44cm., whilst the left twin 

 similarly measures 46cm. The umbilicus is single, and common to both 

 twins, and contains three vessels. Coils of jejuno-ileum are distinctly 

 visible at the umbilicus, shining through the peritoneum. Along the 

 thoracic line of junction is to be felt a distinct bony ridge. 



Dissection. — The abdominal viscera were first dissected out, and 

 thereafter the thoracic viscera. As the various stages of the dissection 

 were identical with those already fully described by Berry in his previous 

 cases (1), it is unnecessary to describe them again. 



