1885.] 



On the Skull in the Mammalia. 



137 



These are (1) the absence of an optic foramen in the embryo; (2) 

 the alisphenoids scarcely overlapping the orbitosphenoids ; (3) the 

 tympanic wings of the alisphenoids are well marked, hollow shells 

 in the embryo; (4) large antero-lateral vomers, and postero -lateral 

 vomers, as large as in average Marsupials, and, as in many of them, 

 meeting and uniting at the mid-line ; (5) a large distinct " os-bul'a3," 

 which makes a tympanic cavity as large as, and much like that of, 

 Petaurus or Phascolarctos. On the high Eutherian side we have, in 

 the embryo, frontals as large as the parietals, and strangest of all 

 Mammalian specialization, a long proboscis, composed of thirty double 

 rings of cartilage, a structure quite similar to the proboscis of an 

 Elephant. The mesopterygoids are suppressed, but the pituitary 

 hole is present. 



I now come to a type for which no place can be found in our 

 (systems of Zoology, but for which the late Professor Peters, in 

 despair, lodged with the Insectivora ; I refer to the Flying Cat (Galeo- 

 pitfiecus). This genus forms a Family by itself, and yet has only two 

 species ; it should form an Order, as the Hyrax does. 



These two species of Flying Mammals are full of remnants of what 

 is old, and rudiments of the new. I put them between the most 

 archaic (Marsupials) and some of the most curiously modified 

 Eutheria, the Frugivorous Bats, and survey them from these two 

 widely separate standpoints; but they possess that which neither 

 Phalanger nor Bat will account for or explain. 



With a flat, outspread, foliaceous skull, as completely ankylosed as 

 that of any bird, and as thoroughly pneumatic in its post-orbital 

 region, we have one of the largest and most perfect hard palates ; 

 with the upper incisors partly suppressed, the lower incisors well 

 -developed and utterly unique, and the premolars and molars strong 

 for grinding. The cheek bones and the squamosals are large and 

 thoroughly Marsupial, so are the small external pterygoid processes 

 and internal pterygoid bones, and the very large mesopterygoids. 

 I find no antero-lateral vomers, but Jacobson's organs and their 

 protecting cartilages are twice as long as in any types yet examined, 

 and the postero-lateral vomers are almost as well developed as in 

 Marsupials, whilst the main vomer is very large. The sphenoid 

 bones are typically Eutherian, but the basisphenoid has beneath it, 

 as in Lizards, a small " parasphenoid ;" this I find only in G. pliillip- 

 pensis, and as yet in no other Mammal. As in the Marsupials, the 

 jugal or malar helps to form the glenoid cavity, and the squamosal is 

 as large as in Cuscus, the lowest of the Eastern Marsupials. The 

 single flat tympanic bone, with its ossified and compressed meatus, 

 is very remarkable; but this part of the skull corresponds neither 

 with the Marsupials nor the Insectivores, and this is true also of 

 several other of its characters. 



