162 MR. ST. GEORGE MIVART ON MICRORHYNCHUS. [Mar. 13, 



little in advance of the posterior margin of the palate. On the other 

 hand, in Microrhynchus there is a very minute one behind the last 

 molar ; but the one near the posterior margin of the palate is of fair 

 size, and there is another, as large, more anteriorly placed. The 

 anterior palatine foramina are very large, relatively larger than in 

 Indris, and both absolutely and relatively larger than in any other 

 Lemuroid. The palate is well ossified and entire, as in Indris, and 

 is of nearly equal width throughout, having somewhat the appear- 

 ance of that of Galeopithecus. 



Its posterior border is not thickened as it is in Indris ; but a pro- 

 cess is prolonged backwards from its middle, as also seems to be the 

 case, sometimes, in the last-mentioned genus*. 



The most anterior point of this posterior margin is on a line with 

 the anterior end of the hindmost third of the second true molar. 



There is a small, but distinct, paroccipital process. 



The foramen rotundum is united with the sphenoidal fissure, and 

 there is a distinct Vidian foramen, thus agreeing with Indris in both 

 these respects. 



There is no conspicuous carotid foramen on the basis cranii. 



The pterygoid fossa is large ; and the ectopterygoid plate sends 

 back a process to the periotic, arching over the foramen ovale. 



The bulla is rather compressed, with an obscure ridge running 

 forwards and inwards along tbe outer part of its inferior surface. 



A marked ridge runs forward (as in Indris and Lemur*) from the 

 anterior root of the posterior origin of the zygoma, across the ali- 

 sphenoid ; but this last sends out no process towards the malar. 



The cribriform plate is wide, and is not situated in a narrow de- 

 pression ; but there is no crista galli. The periotic has a large and 

 deep cerebellar fossa. The mandible is remarkable for the size and 

 the downward and backward prolongation of its angle, for the enor- 

 mous elongation of the symphysis, which is nearly three times the 

 length of the lower incisors, and also for the deep fossa for the in- 

 sertion of the digastric. 



The condyle is not transversely extended, as in Lemur, but is 

 small ; and its articular surface is prolonged downwards behind in a 

 peculiar manner, and is vertically grooved. There is a strongly 

 marked prominence running backwards above the mylohyoid foramen, 

 and another running downwards and backwards beneath and in front 

 of it ; this latter prominence corresponds to part of the inferior mar- 

 gin of the mandible of Indris, and thus in it that margin appears 

 much more strongly concave and the angle to be more suddenly bent 

 downwards than in Microrhynchus. 



In the digastric fossa and non-transversely extended condyle the 

 Indrisince differ from all the Lemuridce, and, as regards the latter 

 character, approach Cheiromys, and closely resemble Tarsius, which 

 has the articular surface likewise prolonged downwards behind. The 

 digastric fossa, however, does not exist in those two genera. Indris 

 shares with Microrhynchus the continuation downwards and back- 



* It is so represented by De Blainville (see he. cit.) ; but in two skulls in the 

 British Museum there is no such median process. 



