SOUTH AMERICAN NEMATOGNATHI. 237 



175 Doras marmoratus. 



JJorrts mnmorrttiis (Reinhardt MS.) Ltltken, Dan. Selsk. Skr. 30, 



1874 (Eio das Velhas), id. 1. o. 1875, pi. i, fig. i; Steindachuer, SB. 



Ak. Wien, Ixxi, 147, pi. iv, 1875 (Brazil); Eigenm. & Eigeiim. 



Proc. Cal. Acad. •2d Ser. i, 163, 1888 (Eio San Francisco; Rio 



das Velhas). 

 Habitat: Eio San Francisco and its tributaries. 



Robust, as deep as wide below the dorsal spine, some- 

 what compressed behind. Head short and broad, its 

 width about equal to its length; its depth If in its 

 length. Dorsal plate greatly enlarged, scarcely narrower 

 than the widest part of the skull, having a backward 

 process which has a downward projection in front. 

 Surface of the bones with vermiculating ridges, which 

 are granular anteriorly and laterally; sutures distinct. 

 Dermal ossification of the scapula not reaching the 

 humeral process. Sides of the head and snout entirely 

 covered with smooth skin. Fontanel scarcely evident 

 externally. 



Eye 2 J in the snout, 7h in the head, 2| in the inter- 

 orbital. Nasal and suborbital bones concealed beneath 

 the skin. 



Maxillary barbels reaching the second fourth of the 

 pectoral spine; mental barbels to somewhat behind the 

 lower angle of the gill-openings, postmentals scarcely 

 beyond base of pectorals. 



Snout at the rictus measuring 2^-25 in length of the 

 head. Upper jaw projecting. * 



Teeth well developed, setiform; intermaxillary band 

 6-8 times as wide as deep. 



Gill-membranes separate to below the posterior mar- 

 gin of the eye. Breast entirely covered with skin. 



First three lateral plates touching the emarginate edge 

 of the process of the dorsal plate, not extending to the hu- 

 meral process; region between the scapula and first lat- 

 eral plate naked; the third lateral plate highest, about 

 2 in the head, the fourth only two-thirds as high as the 



