260 EDWIN CHAPIN STARKS. 



sides, covered with teeth similar to those above ; interhyal pres- 

 ent ; urohyal laterally expanded, broader than high ; parapoph- 

 yses present on all abdominal vertebrae, the posterior ones the 

 largest, much smaller than in Pccci/ia, but otherwise similar. 



Subfamily CYPRINODONTIN.E. 



Characters as indicated by Cyprinodon carpio. 



Interorbital septum single ; a short wide myodome developed ; 

 parasphenoid not sending a lateral process up to alisphenoid ; 

 supraoccipital crest normal ; occipital condyle partly formed by 

 exoccipitals ; prefrontals meeting at the median line ; a small 

 basisphenoid extending upward from the parasphenoid, its upper 

 end unattached ; opisthotic absent ; mandible and premaxillaries 

 normal ; posttemporal widely forked, its upper limb normally 

 joined to epiotic, its lower limb to exoccipital at some distance 

 from the opisthotic region, 1 without the intervention of a liga- 

 ment ; superior pharyngeals as in Fundulus, the teeth sharper, 

 none of them molar ; lower pharyngeals loosely joined to each 

 other, together forming a triangular-shaped bone ; interhyal 

 present ; urohyal normal ; parapophyses as in Fundulits. 



Subfamily PCECILIIN.K. 



Characters as indicated by Pari/ia clongata. 



Interorbital septum double, the sides widely separated through- 

 out ; no myodome ; parasphenoid sending a lateral process up to 

 alisphenoid ; supraoccipital crest expanded laterally on top in a 

 thin hoiizontal wing ; epiotics not produced backwards ; occipital 

 condyle confined to basioccipital ; prefrontals not meeting at the 

 median line ; basisphenoid absent ; a small opisthotic present ; 

 mandible reduced in size, its elements of complex shape, and 

 loosely connected ; side of maxillary turning at a sharp angle 

 with the front ; posttemporal forked, the upper limb firmly at- 

 tached to the cranium, lying closely against the oblique upper 

 surface of the epiotic for nearly its whole length, and leaving 

 scarcely any space between its base and the skull ; the lower 

 fork attached directly to the opisthotic without the intervention 



1 The opisthotic when present in other species covers the suture between the exoc- 

 cipital and the pterotic. 



