1876.] 



On two new Vanadium Minerals. 



109 



in Mus, so that the malleus more resembles that o£ Lepus. The stapes 

 of this family has generally long, slender, and not very divergent crura, 

 and the intercrural canal is wanting. 



In the Hystricidee the great feature is the ankylosis of the malleus to 

 the incus, already well known to zoologists. It is almost invariable in 

 the adults of that family. The manubrium is very broad, and the inner 

 edge above the processus muscularis is very thick. The varieties among 

 the different genera are trifling : the head of the malleus is produced 

 forwards to an extreme degree in Aulamdus, Capromys, and particularly 

 in Chincliilla, but less so in the porcupines and the agouti. The stapes 

 is always proportionally small, with stout and not very divergent crura ; 

 a bony intercrural canal occurs in many genera, but is an inconstant 

 feature in individual specimens of the same species. 



As the ankylosis of the two outer ossicles occurs in Dipus, whilst the 

 head of the malleus remains small and unproduced, and that bone 

 possesses a wide lamina, it must be considered intermediate, as far as 

 those little bones are concerned, between the Muridae and H^^stricidse. 



As occurs in other orders, the fossorial members of the Eodentia pre- 

 sent great peculiarities in their ear-bones. In Geomysthe malleus some- 

 what resembles that of Marmotta ; the stapes is remarkable for the large 

 bulla on its base. Rliizomys and Ellohius approximate most to the rats, 

 Bathyergus to the Hystricidas, which it exceeds in the degree of fusion 

 of the malleus to the incus, which latter bone, however, differs in form 

 from the same in that family. In B]^alax the malleus approaches the 

 more central type of Castor or Lepus ; but the stapes is of a very unique 

 type, somewhat similar to that of Chrysochlons, except that one crus is 

 quite straight and very divergent. 



In both species of Elephajj^t the large ossicula appear rather like the 

 modified ear-bones of certain rodents than like any ungulate. There is 

 neither the lamina or long manubrium mallei, nor the thick and diver- 

 gent processus brevis incudis, nor the quadrilateral stapes frequent 

 among the large Ungulata ; on the other hand the short, broad-based 

 manubrium, the thin, short, and hardly divergent processus brevis of the 

 incus, and the wide intercrural aperture of the stapes are characteristic 

 in Elephas and common among the Hodentia. 



In the Hyraces the ear-bones bear a slight affinity to those of the 

 horse, but none of any importance to the common types among the 

 Ungulata or Eodentia. 



The ossicles of the remaining groups of the Mammalia will be described 

 in a subsequent communication. 



IV. On two new Vanadium Minerals/' By H. E. Roscoe, E.R.S. 

 Received May 10, 1876. 

 No. 1. — The first of these remarkable minerals contains 28 per cent, 

 of vanadium pentoxide. It was forwarded to me by Dr. James Blake, 



