210 BULLETIN 199, UNITED STATES NATIONAL MUSEUM 



KEY TO LIVING FAMILIES OF LORICATA 



1. Dentary teeth 25-26, none received by sockets in upper jaw; maxillary bones 



broadly in contact with each other on dorsal surface of skull; mandibular 

 symphysis extraordinarily long, only 2 or 3 teeth at rear of mandible not 



opposite the symphysis Qavialidae * 



Dentary teeth 20 or fewer, all or nearly all received by sockets in upper jaw; 

 maxillary bones never in contact with each other on dorsal surface of skull; 

 mandibular symphysis shorter, 4 or more teeth at rear of mandible not 

 opposite the symphysis 2 



2. Fourth mandibular tooth fitting into a pit in upper jaw, and 17 to 22 dentary 



teeth Alligatoridae (p. 211) 



Fourth mandibular tooth fitting into a notch in upper jaw or, if into a pit, 

 dentary teeth 16 or fewer .Crccodylidae (p. 210) 



Family CROCODYLIDAE Gray 



Crocodilidae Gray, Ann. Philos., ser. 2, vol. 10, 1825, p. 195. — Mertens, Sencken- 

 bergiana, vol. 26, 1943, pp. 252-312. 



Genera. — Four genera and 17 species and subspecies are recognized 

 at the present time; one genus occurs in the Americas. 

 Range. — World wide in tropical lands. 



Genus CROCODYLUS Laurenti 



Crocodylus Laurenti, Specimen medicum exhibens synopsin reptilium, 1768, p. 53. 

 Molinia Gray, Catalogue of the tortoises, crocodiles and amphisbaenians in the 



collection of the British Museum, 1844, pp. 60, 272 (type, Crocodylus ameri- 



canus Laurenti =? Crocodylus acutus Cuvier). 



Genotype. — Crocodylus niloticus Laurenti. 



Species. — Twelve species, two with two subspecies, are recognized; 

 only four species, one with two subspecies, occur in the New World, 

 and two in Mexico. 



Range. — Northern Australia, New Guinea, East Indies, Siam, 

 Ceylon, tropical Africa and India, Madagascar; southern Florida, 

 Greater Antilles, northern Mexico south to Ecuador and Venezuela. 



KEY TO MEXICAN SPECIES OF CROCODYLUS 



1, Premaxillo-maxillary suture transverse moreletii (p. 211) 



Premaxillo-maxillary suture extending posteriorly in an arc to level of posterior 

 border of seventh tooth acutus (p. 210) 



CROCODYLUS ACUTUS ACUTUS Cuvier' 



Crocodilus acutus Cuvier, Ann. Mus. Hist. Nat. Paris, vol. 10, 1807, p. 55, pi. 



1, fig. 3, pi. 2, fig. 3. 

 Crocodylus acutus acutus, Muller and Hellmich, Ibero-Amerik. Stud., vol. 



13, 1940, pp. 128-130. 



' Not in Mexico; restricted to India. 



• Allocation of the Mexican and, for that matter, Central American specimens is at present very uncertain. 

 South American (Colombia, Ecuador) specimens are referrable to the race C. a. lewyanus, and Santo Do 

 mlngo specimens to C. a. acutus, but no study has been made of material from elsewhere. 



