OF THE MAMMALIAN OSSICULA AUDITUS. 387 



terior segment is much deeper than the anterior ; and the crura are thick, and both 

 divergent. The stapes resembles that of Lemur ; but the crura are stouter. In both 

 the skulls of Propithecus in the College Museum a bony canal passes between the 

 crura of the stapes, as is the case in a skeleton of Indris {Lichanotis) brevicaudatus. In 

 a skull of the Avahi [Indris laniger) I have found the trace of a bare vessel, not supported 

 by bone, instead of an ossified intercrural canal. 



The malleus of Galago (PL LVIII. fig. 22) strikingly resembles that of the Hapalidae ; 

 but the upper part of the head is better developed, the articular surface is still narrower 

 and deeper, and the head is much shorter vertically than in Hapale or Midas. It is 

 quite neckless, and bent very much inwards on the manubrium — an exaggeration of a 

 condition frequent in the mallei of Primates where the neck is suppressed. The manu- 

 brium is slender throughout, even at the base, and ends in a very distinct disk ; there 

 is a processus muscularis halfway down the inner margin. The incus is very high and 

 narrow, as in Nyctipithecus, Pithecia, &c. ; and the anterior segment is actually as high 

 as the posterior, and projects forwards conspicuously. The processus brevis runs in the 

 long axis of the posterior part of the body, with hardly a trace of divergence, the pro- 

 cessus longus diverges extremely. This arrangement of the crura recalls Nyctipithecus, 

 and is usual in the Lorises. The crura of the stapes are slender, and perfectly straight ; 

 the intercrural space is moderate ; and no bony canal appears to occupy it in the 

 recent skull. 



In a specimen of the mallei (PL LVIII. fig. 23) and incudes of Cheirogaleus cookii, 

 the malleus, although resembling Galago in its head and articular surface, has a 

 manubrium which springs from immediately below the articular area of the head, yet 

 bears a distinct projection corresponding to the processus brevis of Man. This pecu- 

 liarity is seen in some squirrels, a family where gradations between the necked and 

 the neckless malleus are as numerous as in the Primates. The handle, too, in Chei- 

 rogaleus is rather flattened naturally. This ossicle altogether is related not distantly 

 to the same in the genus Lemur ; but the incus assumes those conspicuous features seen 

 in Galago ; the divergence of the anterior eras is extreme. There appears to be no 

 bony intercrural canal supporting the stapes in this genus. 



In studying the Nycticebidse or Lorisinae, I find in the malleus of Nycticebus 

 (PI. LVIII. fig. 26) that the characters of the neckless type of that ossicle are all 

 prominent. The head is very short in its vertical measurement, very much bent 

 inwards on the manubrium, and bears a deeply cut but not very wide articular surface. 

 All these features are seen in the Galagos, although the last two are approached in the 

 Marmosets. The singular manubrium is long and very straight ; its outer border is 

 somewhat wavy; and there is a distinct projection and processus muscularis for the 

 tendon of the tensor tympani halfway down the inner margin. The handle terminates 

 in a large disk. The strong resemblance of the malleus of Nycticebus and of some other 

 Primates to the same ossicle in the Tupaiidae and Squirrels is interesting, especially as 

 they are all small thickly furred arboreal animals. 



The incus has a shallow body, quite unlike that of Galago ; but the anterior segment is 

 nearly as high as the posterior. Its articular surface is completely on the top of the 



