380 mr. a. h. g. doran on the morphology 



The Auditory Ossicles oe the Cynomorpha, or Tailed Old-world Monkeys. 



The study of the ear-bones of the Old-world monkeys yields interesting results ; for 

 they all possess certain types in common ; but in comparing them with the Anthropo- 

 morpha we find definite grades of distinction, particularly between Semnopithecus and 

 Macacus. 



In examining the malleus of an Entellus (Semnopithecus entellus, PL LVIII. fig. 7), 

 the free upper portion of its head will be seen to be well developed and globular, dis- 

 tinctly projecting forwards. In the majority of the mallei of this species and genus a 

 distinct fringe of bone, of papery consistence, is found on the front border of the head, 

 joining the root of the processus gracilis (which is stout, stumpy, and very brittle in 

 the Cynomorpha). This (which is the exception in Man, and when existent the fringe 

 never joins the root of our processus gracilis, and is as little indicated in the anthro- 

 poid apes, excepting, perhaps, Hylobates) is a clear approach to the laminated type of 

 malleus seen in the Carnivora, &c. The articular surface is shaped much as in Man 

 and Simla, and is as little divided into the two facets of the typical mammalian malleus 

 as is the case in Homo. The neck is very short, but, being much constricted, is quite 

 distinct. The manubrium forms with the axis of the neck and head an angle of at 

 least 155°, distinctly wider than in any of the last family. This process is of moderate 

 length, though the shortness of the neck makes it look rather longer than it actually 

 is. It is almost of equal breadth laterally, till near the tip, where it turns up rather 

 sharply, and is there discoidal ratfier than spatulate. 



Immediately above this dilatation is a distinct convex projection, giving a wavy look 

 to the manubrium seen in many lower monkeys. There is always a well-developed 

 and everted processus brevis in this genus ; and on the inner edge of the handle, above 

 the projection just described, on the opposite or outer margin, is a distinct " processus 

 muscularis " (as Hyrtl styles it, in describing the carnivorous malleus, and as it will be 

 henceforward designated in this paper), to which, in the recent skull, the tensor tympani 

 muscle will be found attached, as I have verified by dissection. Its position in this 

 and in neighbouring genera, well down the manubrium, reminds the observer of the 

 same process in Eerpestes and in many Rodents. 



In its very distinct though very short neck, and well-developed processus brevis, the 

 malleus in the genus Semnopithecus resembles the Simiidse more than any of the fol- 

 lowing genera except Golobus, where we find similar characters ; but there the form 

 of the head is different. But the wide angle between the body and manubrium, the 

 peculiar form of that process, with a tendency to a discoidal termination, and the 

 presence of a distinct processus muscularis, as well as the trace of a lamina between 

 the head and processus gracilis, are points that ally this genus far more closely to other 

 Old-world monkeys. 



The incus, on the other hand, in all the skulls of this genus which I have examined, 

 more resembles that of the anthropoid apes than in. the succeeding genera, being broad 

 in the body, measured horizontally, and not very deep, with a considerable distance 

 between the origin of each crus, which diverges as much as in Man. 



