84 PROFESSOR OWEN ON THE AYE-AYE. 
the Quadrumana; yet, as the difference depends on the non-claviculate character of 
the Carnivora, a remnant only of the clavicular strip of the muscle being present in 
those with small free clavicular bones, as the Felines, and being wanting in those without 
clavicles, we cannot derive the same evidence of the ordinal relations of Chiromys 
when we extend the comparison to the myology of those of the Lissencephalous group 
which have complete collar-bones. In the Squirrels, e. g., a clavicular strip exists, 
which differs from that of Chiromys only in its minor relative size to the sternal portion. 
The well-developed digastricus, with its distinct intermediate tendon, is a more decisive 
mark of the Lemurine affinity of Chiromys, as against the Rodents. In the muscles of the 
jaw of Chiromys, although the masseter has unusual thickness and strength, it retains 
the character of that muscle inthe Quadrumana, and there is no trace of the peculiarly 
distinct oblique strip, described as an accessory masseter, in the Rodentia,—especially in 
those with the large antorbital vacuity. In the muscles of the limbs, especially in the 
tendinous strip uniting the flexor sublimis and flexor profundus muscles for a partially 
associated action, the Aye-aye resembles the Tarsius dissected by Burmeister, the 
Stenops dissected by Vrolik, and the Perodicticus dissected by Van der Hoeven. 
Comparison of the Brain.—The brain of the Aye-aye, by the proportion and relative posi- 
tion of the cerebrum to the cerebellum, and by the fissures and folds of the cerebral surface, 
determines Chiromys to be a member of the wave-brained section of Mammalia, Gyrence- 
phala ; and in that section it most resembles, in the number and disposition of the primary 
convolutions of the cerebrum, as well as in general shape and proportions, the brain of 
Lemur proper. The brain of the little Tarsier (C. tarsius), whilst exhibiting the more con- 
stant and essential gyrencephalous character, as do other diminutive species, in the exten- 
sion of the cerebrum over the cerebellum, shows an almost entire absence of superficial 
fissures. In that of the Tarsius figured by Burmeister ', the fore part of the sylvian fissure 
and the short vertical fissure in the sylvian fold are all the traces of convolutions which 
are indicated. In the brain of the Javanese Slow Lemur (Stenops javanicus), described 
and figured by Schroeder Van der Kolk and Vrolik, the sylvian fissure extends to 
the upper surface of the cerebrum; the Aye-aye, in this respect, being intermediate 
between Stenops and Tarsius. The sylvian fold, in Stenops, is also indented by the 
vertical fissure, which is more wavy than in Chiromys or Tarsius ; but the suprasylvian 
and medio-longitudinal fissures are wanting in Stenops as in Tarsius. Stenops, however, 
shows the bifurcate anterior ends of the medio-longitudinal fissure, and a transverse 
intacte. I] est évident qu’on en a retiré, aprés l’empaillage, le tarse aujourd’hui manquant, et tout fait supposer 
(je ne puis dire atteste, parceque la piéce n’est pas sous mes yeux, et qu’il ne subsiste aucune note au sujet de 
cette opération) que le tarse figuré comme ¢tant celui de l’Aye-aye est bien, comme vous l’avez supposé, le tarse 
du Galago crassicaudatus. 
«J’ai pensé que ces détails vous feraient plaisir, et je yous les communiquer immédiatement. 
*«Croyez 4 mon entiére considération et 4 mon affectueux dévouement, votre trés-empressé, 
«Paris, 28 Octobre, 1862.” 
“Pau Gervals.” | 
‘ Op. cit. p. 30, pl. 1. figs. 1-4. 
