1894.] NATURAL SCIENCES OF PHILADELPHIA. 45 



and the name given to it by Cuvier of grand aile or its English equiv- 

 alent alisphenoid (Owen) retained." If the bone No. 6 in the skull of 

 the python (Fig. 7), turtle (Fig. 10), alligator (Figs. 9, 11), be 

 compared with that so numbered in the cod-fish (Fig. 6), it will 

 be found that while it resembles the latter in articulating with the 

 basisphenoid and parietal bones, entering into the formation of 

 the lateral wall of the cranium, presenting a notch or foramen for 

 the transmission of the superior and inferior maxillary branches 

 of the fifth nerve and protecting the anterior part of the organ 

 of hearing, it differs from it in transmitting the filaments of the 

 portio dura and mollis of the seventh nerve and in forming the 

 anterior half of the fenestra ovalis of the vestibule. 



In the latter respects, and in protecting the anterior part of the 

 labyrinth, the bone No. 6 in the reptile certainly resembles 



Fig. 10. Interior view of auditory region of turtle. 



the upper or prootic part of the human pars petrosa and would 

 be more appropriately named, therefore, the prootic than the bone 

 No. 6 in the fish. The fact, however, of this bone in the reptile 

 transmitting by notch or foramen'^^ the maxillary branches of the 



2" It should be mentioned in this connection that there are present in the 

 skulls of certain fishes (salmon and carp) three bones which have been regarded 

 as the prootic, alisphenoid and orhito-splienoid. As the latter bone, the most 

 anterior of the three, is, however, inconstant and as we regard it when present as 

 an interorbital bone, not the orltito-splienoid, its presence or absence will not 

 affect the argument as stated above, the so-called prootic in the carp, for ex- 

 ample, being the alisphenoid, and the alisiihenoid being the orbito-sphenoid. 



2« It will be observed in the case of the python (Fig. 7) that the two foramina 

 in the bone No. 6 are as well marked as the foramen rotundum and foramen 

 ovale are in the alisphenoid of Man. 



