14 PROCEEDINGS OF THE NATIONAL MUSEUM. "^ol. 57. 



grown specimen, however, shows that this bon}' bar is made u]) of 

 two separate pieces, as in the opossum, and evidently ossifies from a 

 distinct center in Meckel's cartilage, in advance of the processus gra- 

 cilis. This piece seoms to be widely separated from any part of the 

 malleus in the adult skull and is more or less joined to the tympanic. 



In the jugal arch of SarcopMlus there is some evidence that it is 

 ossified in the same way as in the opossum, namely, from three cen- 

 ters, but I have no embryos young enough to establish this with cer- 

 tainty. There is also evidence that there is a separate bone between 

 the lachrym.al and frontal in front of the orbit. Another point of 

 unusual interest in the skull of SarcopMlus is the presence of a dis- 

 tinct bone just beliind the external auditory meatus at the lower 

 point of junction of the squamosal with the mastoid. This bone, as 

 we shall present!}^ see, is a very constant feature of the skull of the 

 Carnivora, occupying the same position and having the same rela- 

 tions as in SarcopMlus. It probably also exists in the Dasyures, but 

 I have not observed it in any other of the Marsupials. It is often 

 met with in Erinaceus, however, and probably also in Centetes, 

 Ericulus, Solenodon, and others. As this bone is such a constant 

 feature of many of the Carnivora I propose for it the name of para- 

 ma stoid. 



The skull of a young kangaroo in the collection (No. 211) is of 

 especial interest as showing the presence of a free premallear element, 

 consisting of a relatively large triangular piece of bone, overlapping 

 the tympanic, and intimately associated with the forward extension 

 of the processus gracilis. This specimen furnishes confirmatory evi- 

 dence, together with that already noticed in the opossum and Sar- 

 copMlus, of the statement of Parker, presently to be quoted, that in 

 Phascolarctos there is a separate and distinct element developed m 

 connection with Meckel's cartilage in front of the malleus. 



The following species of Marsupials in the collection shov; the 

 presence of an extra element at the junction of the malar with the 

 zygomatic process of the squamosal not dissimilar to that described 

 in Rhyndiocyon, na,mely, Macropus irma (No. 155372), PseudocMrus 

 lemuroides (No. 38714), Phalanger, sp. (No. 38470), Dasyurus macu- 

 latus (No. 38444), SarcopMlus ursinus (No. 155385), DidepMs vir- 

 ginanus (No. 61842), and MetacMrus opossum (No. 121414), 



Oheiroptera. — Among the fruit-eatmg bats there are a number of 

 species which show undoubted traces of these archaic characters. In 

 Pteropus there are traces of a distinct bone, developed in connection 

 with the postorbital process of the frontal above the eye; there is 

 evidence of a separate element composing the postorbital process of 

 the jugal, as well as less distinct evidence of a division of the malar 

 into two parts. In young skulls there is always a distinct bone devel- 

 oped in connection with the anterior portion of the tympanic ring, 



