122 GILL, SYNOPSIS OF THE 



§1. SYNOPSIS. j 



\ 

 Suborders. 



I. Intermaxillaries expanded forwards, normally inter- | 



posed between the maxillaries, and forming the ter- 

 minal as well as anterior portion of the lateral mar- i 

 gin of the upper jaw. Nasal apertures produced j 

 more or less forwards. Teeth of the intermaxilla- 

 ries apparently in normal number (3+3), conic; of , 

 the maxillaries, 2- or 3-rooted. ZEUGLODONTIA. | 



II. Intermaxillaries narrowed forwards, forming only . | 



the point of the lower jaw, and underlaid by the 

 maxillaries, which form the entire lateral alveolar 

 margins of the jaw. Xasal apertures far back, near 

 the vertex. Teeth (when present) all single rooted. 



1. Teeth persistent after birth. Upper jaw without 



baleen. Eami of lower jaw united by a symphi- 



seal suture. Olfactory organ rudimentary or ab- i 



sent ; the nasal bones being appressed on the fron- I 



tals and overlapped distally. DENTICETE. j 



2. Teeth absorbed and disappearing before birth. Up- i 



per jaw provided with plates of baleen. Kami of t 



lower jaw not united by suture. Olfactory organ ] 



distinctly developed ; the nasal bones projecting | 

 forwards, and free at their distal ends. MYSTICETE. 



ZEUGLODONTIA. | 



FAinuES. i 



I. Anterior nares open forwards ; nasal bones elongated. ' 



BASELOSAUEID^. (I.) | 



n. Anterior nares open far beliind; nasal bones short. ] 



CTyOECIDuE. (n.) 

 I. BASILOSAURTD^ Cope. 



n. CTNORCID^ Cope. | 



DEKTICETE. 



Famtt.tes. 



A. Eostrum of skull with a rounded apex. 

 I. Upper jaw rostrated and attenuated, or ledge-like 

 around the margin. Skull with the vertex pro- 

 duced forwards. Supraoccipital not projecting 



