MUSEUM OF COMPARATIVE ZOOLOGY. 149 



inferred from this statement that the ethmoid bone in the bats differs 

 in any essential feature from the bone as above described. In the 

 more generalized forms, as the Pteropines and in most of the Phyllosto- 

 mines, the ethmoid, while simple in construction, is in general appear- 

 ance much the same as in other mammals. But in the more specialized 

 genera, the details are so strongly contrasted with those of the mamma- 

 lian type, (presenting .a number of characters, which it is thought may 

 be of value in classification,) that the special attention of the reader is 

 invited to their consideration. 



Descriptions of the Ethmoid Bone, including all its Parts. 



Pteropus medius. — The encranial surface presents a small ectoturbi- 

 nal space, which, however, is as wide as the union of the septoturbinal 

 and endoturbinal spaces farther backward. The cribriform is thus nar- 

 rowed, and without conspicuous ridges or other markings than the 

 median and lateral rows of foramina. The non-perforatc surface is a 

 mere narrow rim. 



The ethmoturbinal mass is much compressed laterally, and composed 

 of a single ectoturbinal and a series of four endoturbinal plates, which 

 are united anteriorly and laterally. The tendency for the endoturbinal 

 plates to form parts of one functional surface recalls the disposition of 

 the parts in the Quadrumana. The opening above the endoturbinal 

 series is distinctly median. The first plate lateral to this opening would 

 he the nasoturbinal, which here does not appear to be different from the 

 usual disposition of an ectoturbinal, and I have concluded so to name it. 



The ectoturbinal extends as far as the plane of the anterior border of 

 the first molar. It is higher at its origin from the crihriform plate than 

 at its anterior free end. It is curvilinear and convolute outward. It is 

 attached its entire length to the lateral surface of the ethmoturbinal 

 mass, and anteriorly to the endoturbinal transverse lamina. 



The endoturbinal series of plates are united by a broad transverse 

 lamina, which anteriorly (i. e. beyond the point of its union with the 

 vomer) is deeply concave on its free under surface, so as to cover in the 

 maxilloturbinal. 



In a profile view of the median surface of the ethmoturbinal series the 

 vertical aspect of this concave surface is distinctly seen, and ii 

 resembles a lobe; but it is not traceable to any one olfactory plate. 

 The transverse lamina is traceable backward to the anterior ends of all 

 the olfactory plates, including the ectoturbinal. The lower anterior 

 half of the median surface of the plate is emarginate. The anterior 



