33 



f. 4) foimded his genus Hipparionyx on a species to wliich 

 Le gave the name of xiroximiis^ and which has been fully 

 illustrated by Prof. Hall under the name of Orihis li'ippa- 

 rionyx in Pal. JT. York, vol. iii. Subsequently Prof. Hall 

 (Sixteenth Regent's Eep. p. G5) refers to this species as an 

 extreme form of the genus Streptorhynchus of King, which, 

 if true, would reduce Prof. King's name to a synonym, since 

 Vanuxem's genus rests on the character of its type, and its 

 validity is not affected by the original inclusion with that 

 type of species not congeneric. 



Prof. King, in 1850 (Perm. Foss. p. 107), erected into a 

 genus the Terehraiula peJargonata of Schlotheim, under the 

 name of Streptorhynchus. This and 0. crcnistria were for 

 some time afterward included by Davidson in Orthisina ( = 

 Klitamhonites), but have since been separated from that con- 

 nection, and recognized by him as species of Streptorhynchus, 

 which he adopts as a section of Strophomcna. 



In 1804, Mr. P. B. Meek (Pal. Upper Missouri, part i, p. 

 25) expresses the opinion that Streptorhynchus is not sepa- 

 rated by any definite characters from Hemipronites, as he 

 understood it { = Strophome7ia, Blainville), and with Hippa- 

 rionyx unites the two under Pander's name, which he adopts. 

 In 1873 (1. c), Mr. Meek, being unaware that Eafinesque's 

 genus Strophomenes had not been described prior to Blain- 

 ville's description of Strophomena., and relying on the state- 

 ment that a specimen of the Anomites rhomboidalis of Wah- 

 lenburg had been labelled Strophomena rugosa by Raflnesque 

 himself, proposed to adopt that as the type of Strophomena 

 (a name never published by Rafinesque), and to retain the 

 typical species of Blainville and its congeners under the 

 name of Hemipronites. In Pal. Ohio, ii, p. 281, Mr. Meek 

 reiterates his opinions of 1864 and 1873. If the proposi- 

 tions upon which this opinion was founded, namely, that 

 Pander's type of Hemipronites was a " true Streptorhynchus 

 of King", and that between the latter and the Strophome- 

 noid forms typified by S. planumhona there is no difference 

 except of degree, had proved unassailable, no question would 

 arise as to the propriety of his conclusions. 



However, since 1863, numerous investigations have re- 

 3 



