THE BATRACHIA OF NOETH AMERICA. 383 



This genus exhibits also an external corpus adiposuni, which I have 

 not found in Callula, Engystoma, or any other genus of Batrachia. 

 Each one is subtrihedral, the apex resting near the extremity of the 

 coracoid, the body lying between the strata of the external and in- 

 ternal oblique muscles, along the anterior margin of the lobe of the 

 liver on each side. 



There are some important skeletal characters found in this genus, 

 whose value is not yet clear. Thus the suspensorium is free, and has 

 an anteroposterior movement on the prootic. This is due to the form 

 of the squamosal, which has no zygomatic process, and is not united by 

 suture with the prootic. The quadrate cartilage is all that connects it 

 with the cranium. A similar structure exists in Breviceps and Callula 

 (Plate 75, figs. 1-2). The frontoparietals are coossifled with each other, 

 as are also the prefrontals. 



The hyoid apparatus is peculiar (Plate 56, fig, 18). The fourth, cera- 

 tobranchials are ossified and i)roximally incurved, and in close contact 

 with each other, thus surrounding the larynx in front. They are only 

 coDrnected with the basihyobranchial plate by membrane. The latter 

 has a rc'-'irved transverse anterior margin, and sends a process forwards 

 on eacL side to the incurved and thin ceratohyals. The third cerato- 

 branchials are elongate and ossified distally. This kind of hyoid ap- 

 paratus further distinguishes the family HemisidiB from all others. 



FIRMISTERMA. 



Bouleuger, Cat. Batr. Sal. Brit. Mus., od. ii, 1882 (luiuus Gastrecbmia); 

 Firniisteruia aud Raniformia, Cope, Check-List IST. Aiiier. Batr., 

 Reptil.; 1877; Rauiformiaaud Bufoniformiapt., Cope, Nat. Hist. Rev., 

 1865. 



The families of this superfamily are the following: 



T. No teeth on the maxillary or premaxillary boues : 



Prajcoracoidei j)reseiit ; sacrum witli dilated triaugular diapophyses, confluent 



with coccygeal style ; two lobes of the liver B^-vvicijntida;. 



Praicoracoidei wanting; sacrum distinct from coccygeal style, with dilated tri- 

 augular diapophyses ; two lobes of the liver Engijstomidm- 



PnBcoracoidei present; sacrum distinct from coccygeal style, Avitli dilated tri- 

 angular diaiiophyses ; two or three lobes of the liver Fhryniacidw. 



Pra3coracoidei present; sacrum distinct from coccygeal style, with cylindrical 



diapophyses ; three lobes of the liver Dendrohalidcc. 



II. Maxillary aud premaxillarj' bones toothed: 



Praicoracoidei absent; sacral diapophyses dilated; mandible edentulous 



, Copliijlidw. 



Prajcoracoids present; sacral diapophyses expanded; mandible edentulous 



Dijscopliida;. 



Prajcoracoid present; sternum and omostcrnum w-anting ; three lobes of the liver; 

 mandible edentulous Colosteihidw. 



Pnecoracoid iiresent ; sternuai and omosternum present, osseous; three lobes of 

 the liver ; mandible edentulous Raiddm, 



Praicoracoid present; sternum styloid; sacral diapophyses cyllndric; mandible 

 dentigerous Ceratohatrachidw. 



