MAY, 1921. AMERICAN MARSUPIAL, C^NOLESTES OSGOOD. 97 



metatarsals respectively. The ectocuneiform is about twice as large as 

 the mesocuneiform and nearly four times the size of the entocuneiform. 

 The hallux is supported on the distal end of the ectocuneiform more 

 especially toward its plantar side and has considerable freedom of 

 movement, although it is but slightly divergent. It is much more slender 

 than the other digits and its terminal phalanx reaches only to the distal 

 extremity of the second metatarsals. The proximal bases of the meta- 

 tarsals form a very uneven row. The fifth reaches farthest proximad, 

 the second and third are considerably short of it, and the first and 

 fourth are still more so. The irregularity in this respect is greater than 

 in any other forms examined. The second and fifth extend distad about 

 the same distance and are slightly exceeded by the third and fourth 

 which also end evenly. The fourth however is somewhat longer than 

 the third by actual measurement since the uneven bases give it greater 

 extension proximad. In a male specimen it is 9 mm. long. The first and 

 also the second phalanges are approximately equal in length from the 

 second to the fifth digits. The paired sesamoids on the metatarso- 

 phalangeal joints are as usual. There is no prehallux. 



SUMMARY OF SKELETAL CHARACTERS. 



The skeleton of C&nolestes has the broad general features found in 

 most other marsupials. With the exception of modifications correlated 

 with cursorial limbs, most of its peculiarities are of a primitive or 

 generalized nature rather than of high specialization. The movable 

 cervical rib and the very short pubic symphysis are examples. The 

 general form of the pelvis is remarkably similar to that of some insecti- 

 vores. In fact the whole skeleton in its general aspects is so closely 

 paralleled by that of one species of insectivore (Nesogale dobsoni), which 

 chances to be available, that the two have been illustrated together 

 (PI. XIX). 



Skeletons of the following marsupials have been available for com- 

 parison: Antechinomys laniger, Sminthopsis crassicaudata, Phascologale 

 (Chcetocercus) cristicauda, Dasyurus viverrinus, Thylacinus cynocephalus, 

 Sarcophilus harrisi, Didelphis virginianus, Marmosa marica, Peramys 

 domesticus, Philander laniger, Myrmecobius fasciatus, Perameles nasuta, 

 Petaurus australis, Trichosurus vulpecula, Phascolarctos cinereus, Mac- 

 ropus giganteus, and Phascolomys mitchelli. A larger representation 

 would have been desirable and it is possible that some conclusions will 

 need modification when wider comparison is made. Numerous minor 

 peculiarities of general characters of the skeleton have been discussed 

 in preceding pages. 



