1882.] J. Cockburn — Abnormality in Jiorns of Hog -deer. 71 



communications — who, while residing in the neighbourhood o£ any region 

 which has not yet been explored by Europeans and is still a terra incognita 

 to the world at large, devote themselves to enquiries regarding its inhabi- 

 tants, their actual subdivisions, and the general run of the rivers and 

 mountain ranges which separate them from each other and from the outer 

 world. In this way the broad facts of the geography of the country be- 

 come elicited even without actual survey. 



The information now furnished by Mr Lepper and A. D. regarding 

 the Singphu Kampti country and the regions between eastern Assam and 

 western China tends to strengthen the probabilities in favour of the sources 

 of the Irrawaddy river lying wholly in a system of mountain ranges on or 

 about the parallel of 28''. On the other hand we have already learnt from 

 A. D. that the Salwin river — which may be regarded as a sister to the 

 Irrawaddy, the two flowing parallel to each other for a considerable dis- 

 tance, and eventually entering the same ocean — takes its rise in the great 

 plateau of eastern Thibet, probably about the parallel of 32,° and very 

 considerably to the north of the sources of the Irrawaddy. This is a fact 

 of considerable geographical importance, of which we might long have 

 remained in ignorance but for these communications. 



6. On an ahnormalitg in the horns of the Hog-deer, Hyelaphus porcinus, 



Zim, with a theory on the Evolution of Antlers in Buminants. — By 



John Cockbuen. 



(Abstract.) 



The abnormality whicb was unilateral was described and attributed to 

 reversion to an ancestor of both Businae and Elaphince, The arguments 

 for and against this decision were then discussed. 



Mr. Cockburn alluded to Prof. Garrod's theory of development from a 

 typical antler which might be described as a bifurcate beam with a brow 

 antler at the basal portion. 



The author regards this typical antler as already a complex organ, in- 

 asmuch as certain existing species of deer show a far more elementary 

 type, Cervulus and Coassus rufas for example, the horns of the latter 

 animal never proceeding beyond the condition of a simple spike. 



The important fact that the antlers of all ruminants exhibit the ele- 

 mentary character of a simple spike in the first year's growth has caused 

 the author to assume as a hypothesis that the development of the antlers of 

 individual species of Gervinae is a recapitulation of the history of the 

 development of antlers in the group. The details of the theory are then 

 explained and Prof. Boyd Dawkin's latest researches alluded to. 



