Lect. VIIL] LEMURS AND AYE- AYE. 195 



in my Memoir on the " Shoulder- Girdle and Ster- 

 num." 



The Hare tribe (Leporidse) are not only non-typical in 

 their teeth, but their front palate, as Mr Howes has 

 shown me, is very different from that of other Mammals. 

 The bulla tympani is not distinct from the annulus, in 

 Eodents, but this part is very large ; the Eustachian tube 

 is lined with cartilage derived from the meatus (or carti- 

 laginous outer ear), and outside the bony annulus another 

 imperfect ring is found in some kinds. Outside this 

 the rings of the meatus externus (ear-porch) get less 

 and less distinct, until the large concha (or projecting 

 ear) is reached. The whole structure of the outer ear 

 of a Eodent is similar to the nose-tube in the Hag-Fish, 

 below, among the fishes, and in the probiscidean Rhyn- 

 chocyon, and the Elephants, above, amongst the high 

 types ; the nose- tube is, of course, single in the Fish, 

 but double in the Mammal. 



Lemuroidea (Lemurs and Aye- Aye). 



The Lemurs are a most puzzling group, no one 

 knows where to put them ; they used to be placed 

 with the Primates, because they have four hands 

 (are c[uadrumanous), but they are now considered 

 to be worth a separate stall. They are marvellously 

 like the Monkeys, but are very inferior to them in 

 every respect, lower in intelligence, and more archaic 

 in type. Therefore, the present Lemurs are not the 



