2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I49 



ever, except for a fragment of a lower incisor 50 mm. in length, 

 Schreuder had only cranial fragments and the upper dentition of 

 Amblyrhiza, all of which were mature, whereas, except for the 

 three postcranial scraps and a fragment of an upper incisor 19 mm. 

 in length, Quemisia is known only from an immature lower jaw. 

 Obviously, close comparison between Quemisia and Schreuder's 

 specimens of Amblyrhiza is impossible, and, although mandibular 

 material of Amblyrhiza is available, the closely related Elasmodont- 

 omys can be more usefully compared to Quemisia in that the two are 

 known from jaws of comparable ontogenetic age and are similar 

 in size. 



In fact, however, in most characters except size and some de- 

 tails of dentition, Quemisia is dissimilar to Elasmodontomys and 

 similar to the Capromyidae, in particular to Plagiodontia (figs. 1, 2). 

 Interestingly, most of the features in which Quemisia differs 

 from Elasmodontomys were well described by Miller, who never- 

 theless failed to recognize that these very features seem to ally 

 Quemisia with the Capromyidae. Most of the comparisons of 

 Quemisia with Elasmodontomys and Plagiodontia are straightfor- 

 ward and are most readily comprehended in tabular form (table 1). 



The interpretation of the enamel configuration of the cheekteeth, 

 however, is more complex and requires some discussion. The oc- 

 clusal surface of each cheektooth in Quemisia is dominated by three 

 deep, narrowly compressed reentrant folds, two lingual (anterior) 

 and one labial (posterior). The Ungual reentrants extend to or 

 almost to the opposite, external enamel wall but do not breach it 

 (except very shallowly in the anterior fold of the unworn M 3 ). 

 The labial reentrant is completely penetrant, producing on the oc- 

 clusal surface an isolated posterior enamel island. However, the 

 depth of penetration on the lingual wall by this reentrant is very 

 shallow, especially in the first cheektooth, so that with slight addi- 

 tional wear this fold would have assumed the character of the 

 lingual ones. In Elasmodontomys the lingual reentrants are com- 

 pletely penetrant apically, as is the labial reentrant, thus generally 

 producing in moderately worn permanent lower cheekteeth a pat- 

 tern of four obliquely oriented complete enamel ellipses succeeding 



p. 13) and Latinized by Fischer (1830, p. 389[=589]) as C.[=Capromys] 

 quemi. Allen (1942, p. 128) pointed out that if Miller's supposition were correct, 

 then the scientific name should be Quemisia quemi. However, it seems highly 

 improbable that the identity of Miller's Quemisia with Oviedo's "Quemi" could 

 ever be established beyond reasonable doubt. Thus, Qwmisia quemi is best 

 regarded as a nomen dubium. 



