1889.] Synopsis of the Families of Vertebrata. 86 1 
a. One occipital cotyloid articulation. 
Vertebral bodies represented by basal and lateral 
elements (intercentra and centra) ; Ganocephali. 
aa. Two occipital condyles. 
Vertebrae represented by distinct and incomplete 
intercentra and centra (pleurocentra) ; atlas 
segmented ; Rhachitomi. 
Centra and intercentra complete, making two ver- 
tebral bodies to each neural arch ; Embolomeri. 
No centra ; intercentra, each supporting a neural 
arch ; Microsauri. 
II. Basioccipital, supraoccipital, and supratemporal bones 
wanting ; propodial bones distinct ; no urostyle {Urodela). 
a. An OS intercalare. 
Palatine arch and vomer present ; Proteida. 
aa. No OS intercalare. 
A maxillary arch and vomers ; Pseudosauria. 
No maxillary arch or vomers ; Trachystomata. 
III. Basioccipital, supraoccipital, intercalare, and supratem- 
porals wanting ; frontals and parietals connate ; propodial 
bones connate ; lumbosacral vertebrae united into a uros- 
tyle {Salientid). 
A palatine arch and vomers ; Anura. 
STEGOCEPHALI. 
Of the Ganocephali two families are known, the Trimeror- 
hachidse without, and the Archegosauridae with neural spines 
of the vertebras. 
The Rhachitomi possess but one family, the Eryopidae. To 
this family belongs the Labyrinthodontia. 
Of the Embolomeri one family is known, the Cricotids. 
The Microsauri embraces the following families; Branchio- 
sauridae; Hylonomidae ; Molgophidae ; Phlegthontiid«. 
URODELA. 
Under the Proteida the only family known is the Proteidse. 
~' nbraces the following families : Crypto- 
