Occasional Papers of the Museum of Zoology 5 



a little curved towards the back. Perhaps a peculiar S. G. 

 near to Epioplasma, it might be called Lemiox." 



This species was first identified with the well known Unio 

 ccclatus Con. by Frierson (Naut. XXVIII, 1914, p. 7), and 

 the identification has been accepted by Ortmann (Xaut. XXX, 

 1916, p. 39) who considers the species (ccclafus) worthy of 

 generic rank on account of its unique surface sculpture and 

 certain anatomical pecularities. 



The validity of the use of Lemiox as the name for this 

 genus depends upon the certainty of the identilication of 

 rimosus with ccclatus. This approximation rests wholly upon 

 Rafinesque's use of the word, "rimose" as a descriptive term, 

 as aside from this the species would be wholly unidentifiable. 

 According to the Century Dictionary rimose means "chinky, 

 like the bark of a tree" and in entomology the surface sculp- 

 ture of insects showing "many minute, narrow and generally 

 parallel excavations." While at first blush it must be ad- 

 mitted that this seems quite an apt description of the peculiar 

 surface sculpture of ccclatus, it is not exactly correct and the 

 remaining characters given by Rafinesque for his species do 

 not at all apply. He says that the shell of his species is nearly 

 smooth, that it is broader and rimose behind, and that it is one 

 and one-half inches long, the altitude being 2/3 and the 

 diameter 1/6 of the length. X^one of these are true of ccclatus, 

 the corrugations are not minute, but are very heavy and coarse, 

 they are not confined to the posterior portion, but cover three- 

 fourths of the entire shell, which is not wider behind, and the 

 diameter of a specimen of ccclatus of the length given by Rafin- 

 esque is nearly one-half instead of one-sixth of the length. 



Rafinesque's description would apply much better to Me- 

 dionidus conradicus Lea than it does to ccclatus Con. The 



