SOUTH AMERICAN NEMATOGNATHI. 399 



t. Superciliary edge not raised, interorbital highest in the middle, 

 orbit moderate 3 (in specimens .16m.)-3 (in specimens .30 m.) 

 in the snout, 5-6| in the head, 2 in the-interorbital; postf ren- 

 tals with a long descending process which forms the entire poste- 

 rior margin of the eye; dorsal spots as large as or a little smaller 

 than the eye. Lat. 1. 26. lima 358. 



t' . Fins all uniform dark brown. lima atropinnis 358a. 



ft. Superciliary edge greatly raised, interorbital area concave; 

 orbit large, 3 in the snout, 5 in the head, If in the interorbital; 

 postfrontals without a descending process, forming part of the 

 upper margin of the orbit only; dorsal uniform dusky. Lat. 1. 

 27. macrops 359. 



rr. Tip of snout granular; eye 6| in the head; more than 2 in the in- 

 terorbital; head 3; base of dorsal larger than its distance from the 

 adipose. Olive brown with one or more orange yellow spots on 

 each lateral scute, similar ones on the head, dorsal and caudal. 



francisci 360. 

 qq. Belly partially or wholly naked; tip of snout naked. 



u. Each of the large scutes with two or three small, round yellow 



spots; eye 2 in the interorbital; thorax nearly entirely covered with 



granulations, sides of the belly naked; anterior dorsal rays much 



longer than the head; caudal subtruncate; pectoral spine broad 



reaching 2nd third of the ventrals, its upper surface with slender 



curved spines; scutes granular, not keeled; head little more than 



\ of the length. Lat. 1. 27. (Giinther.) alatus 361. 



uu. Sides of the body and the fins with irregular longish yellow spots, 



sometimes confluent into bands; head with round dark spots; head 



as wide as long; eye 3| in the snout, 5^ in the head, more than 2 in 



the interorbital; caudal subtruncate; irregular granular patches on 



the throat, breast and belly, the granules on the middle of the belly 



smallest; first dorsal ray equals the length of the head. Lat. 1. 27. 



(Kner.) auroguttatus 362. 



uuu. Sides of the body usually with round dusky plates; fins with 



similar spots or plain. Head longer than broad. 



v. Occipital bordered by two or three nuchal plates*; base of dorsal 



almost equal to its distance from the caudal; lateral plates striate 



not keeled. 



w. Caudal plain, spots on the head and on the dorsal not conflu- 

 ent into lines or bars; ventral surface plain, with very few 

 granules; head 3. lutlceni 363. 



ww. Caudal with wavy crossbars formed by dusky spots on the 

 rays; spots on the head sometimes confluent into vermiculating 

 lines; ventral surface plain, with very few granules. 



vermicular is 364. 



* Not examined in brevicauda. 



