144 BULLETIN OF THE 



appear to be al)sent in the ape, at least in the adult. In man they 

 are also absent. The opossum has two cctoturbinals ; the cat, two to 

 three ; the hrxj, five ; the ox, eight. In the seal the ectoturbinals are 

 developed to a greater degree than the euiloturbiuals. 



The oltactory plates are either simjile at tlieir ends or convolute. 

 Their anterior ends are often produced forwards in a scries of tongue- 

 like projections, which have received the name of the olfactory lobes. 

 The projection known as the nasoturbinal is the most conspicuous of 

 these. The lobe on the first endoturbinal is always well developed. 

 The cndoturbinals of the luxj are without marked lobulations. 'I'lic 

 Carnivora and the liodentia, as far as examined, possess lobes on all 

 the folds. In the ojoossum two of the plates are simple, the remainder 

 are convolute. Occasionally a convolute fold arises from the side of a 

 plate instead of from the end, as iu the larger plates of the Carnivora 

 and the Uuminantia. The arrangement of the cndoturbinals, as seen in 

 tlie median surface of the ethmoturbiuals, is nmch the same as in other 

 Carnivora. 



The septoturbinal space is in all manunals narrow, and indeed may be 

 obliterated here and there where the endoturbinal ])lates lie in contact 

 with the septum. Such a point of contact is evident in the macaque, 

 M. nemestrinus, where a depression is seen on the septum answering iu 

 position to the first endoturbinal plate. Similar depressions are seen in 

 the bats, as in Antrazous and Corynorhinus. 



In Ctbas (Plate II. figs. 1, 2) the absence of an ectoturbinal series, and 

 the endoturbinal series being restricted to a single plate bearing incisures 

 upon its posterior border, and retaining upon its anterior surface a de- 

 flected and abortive nasoturbinal (uncinate process), an example is aff'orded 

 of the manner after which the ethmoid bone is modified in passing "from 

 the quadrupedal form to the primate. In man the interval between the 

 endoturbinal series and the lateral aspect of the bone is occupied by a 

 number of cellules. These being absent in Cehii^ and J/acacns (the only 

 genera examined), it would appear as though tiie chief difierencc l)e- 

 tween these forms and the human ethmoid lay in tlie development of 

 the ethmoid cells. 



The human ethmoid bone (Plate II. fig. 3), viewed from beneath, fur- 

 nishes, as in Cchus, an al)orted nasoturbinal in the " uncinate process," 

 and the rugose under surface of the single endoturbinal plate in the 

 " middle turbinated bone." 



A Special Account of the EtJnnoid Pxme in the Horse, the I'eccarij. the 

 Sloth, the Cat, the Seal, and ilie Jfole. — I have tlnis endeavored to 



