1873.] MR. ST. G. M1VART ON THE LliMURS. 485 



8. The transverse diameter of the thorax exceeds its depth. 



9. The dorsal region of the spinal column is relatively very 

 short. 



10. The cartilages of the ribs slightly expand before joining the 

 sternum. 



11. There are no hyperapophyses. 



12. There is no intermedium in the carpus. 



I find, on the contrary, that it differs from /. brevicuudatus in 

 that the groove which extends along the axillary margin of the 

 scapida is not visible on the dorsum of that bone, as also that the 

 anterior inferior spinous process of the ilium is relatively smaller and 

 less prominent. 



There are, moreover, one or two caudal chevron bones ; but these 

 are minute. 



The absolute and relative dimensions of the bones are given in 

 the Table anuexed to this paper. 



The skull and skeleton of I. diadema* are those of a specimen 

 which, from the condition of the teeth, is evidently even more than 

 adult. Comparing it with the description and figure of the im- 

 mature specimen from Berlin before described by met, I find that, 

 with slight differences as to proportion and development of ridges, 

 due to age, it agrees completely, except that there is a minute malar 

 foramen, that the posterior palatine foramen situated behind the last 

 molar cannot be called small, and that the canines are long and 

 pointed and destitute of that production of the anterior margin 

 which exists slightly in Indris brevicaudatus and so largely in 

 /. laniger. 



The size and proportions of the skull are extremely like those of 

 /. brevicaudatus ; but in the adult, as in the young, the muzzle is 

 slightly shorter relatively. 



The axial and appendicular skeletons show also a great resemblance 

 to the same parts in I. brevicaudatus, except that the humerus is 

 relatively longer, and the femur shorter, while the ulna is stouter 

 and diverges further from the radius. 



The scapula and ilium agree with those of I. brevicaudatus in 

 that the former has the axillary groove visible on the dorsum of the 

 bone, and the latter has an anterior inferior spinous process greatly 

 developed ; it is even more developed than in /. brevicaudatus. 



As regards the twelve points above enumerated (as those in which 

 J. laniger agrees with 1. brevicaudatus and differs from the genus 

 Lemur), I find that I. diadema agrees with the other Indrisince ex- 

 amined by me, except that the spine of the axis extends somewhat 

 backwards over the third cervical vertebra. I find no chevron bones 

 attached to the caudal vertebrae ; but they may have been accident- 

 ally lost, as has no doubt been the case with the intermedium of the 

 carpus, since Professor Alphonse Milne-Edwards has been so kind as 

 to inform me that this bone exists in all the individuals (about 



* No. 15336; 70. 5. 5. 2 in the British-Museum collection, 

 t P. Z.S. 1867, p. -'47. pi: xviii. 



