408 PROFESSOR PETERS ON THE GENUS PECTINATOR. 
Conclusions. 
1. Pectinator differs from Ctenodactylus not only in its greater number of teeth and 
longer tail, but also in the different structure of the ears and the skull. 
2. The Ctenodactyli (Ctenodactylus and Pectinator) cannot be associated with the 
Dipodes, their relation to them being not greater than that of the Chinchille, Octodontes, 
and Echinomyes. , 
3. They show in nearly every part of their structure their near relationship with the 
last-named groups, and deviate from them only in a very few points (the form of the 
hyoid bone, of the sacral and caudal vertebral column, of the development of the crest 
of the humerus and femur), in which, however, they do not show any inclination towards 
the Dipodina, but rather some affinity with the Murina. 
4. They form a peculiar group of the Hystricide, as understood by Waterhouse, 
which in some points is more allied to the Chinchille, in other points to the Octodontes. 
5. Petromys is not to be associated with the Ctenodactyli, but with the Octodontes. 
DESCRIPTION OF THE PLATES. 
PLATE XLVIII. 
Pectinator spekii. Natural size. 
PLATE XLIX. 
Pectinator spekii. All figures of the natural size. 
Fig. 1. Skeleton. 
Fig. 2. Skull, from above. 
Fig. 3. Skull, from below. 
Fig. 4. Left side of the lower jaw. 
Fig. 5. Cervical and part of the thoracic portion of the vertebral column. 
Fig. 6. Sternum, episternum, clavicles, and costal cartilages. 
Fig. 7. Pelvis. 
Fig. 8. Femur. 
PLATE L. 
Fig. 1. Left ear of Ctenodactylus massonii, Gray. Natural size. 
All the other figures belong to Pectinator spekit. 
Fig. 2. Snout, in front. 
Fig. 3. Teat of the left side (m), in situ. 
