13 



mentatus; E. sexcostatus ; Zethus bellatulus, witb tlie 

 following synonyms : Orypt. punctatus, variolaris, and 

 Wccrlliii, Eicli., also Z. bellatulus, Volb. He describes 

 Zethus rex, pi. i, fig. 3 ; Z. atractapyge, McCoy, and Z. 

 brevicauda, Aug. 



In 1858, Schmidt, in an article on the Silurian Sys- 

 tem of Esthlands, describes Encrinurus punctatus. 



Doctor Volborth, in the Memoirs de I'Acad. imp. d. 

 Sciences, de St. Petersburg, vol. vi. No. 2, p. 20, 1863, 

 remarks : "Eichwald abandoned his original genus. 

 Crypt onymus, about twenty years ago, and transferred 

 the generic name to other trilobites. He cannot forget 

 this fact, that the genus Cryptonymus of 1825 has pri- 

 ority over Illcenus, which was established in 1826 ; and 

 he refers on every occasion to it, even in his Lethsea 

 Rossica, on p. 1476. In his pg,raphlet on the genera 

 Zethus and Cryptonymus, he endeavors to prove his 

 opinion by taking the absolute majority, remarking : 

 'That of the eight published species of Cryptonymus, five, 

 the majority, belong to the genus Illmnu^, and only three 

 to Asaplius"; the author therefore claims the priority for 

 his genus over Illccnus, which was published two years 

 afterwards. The majority cannot decide this question, 

 but only the total number. The author would have the 

 right to claim his generic priority, if each of the 8 spe- 

 cies of Cryptonymus had the ten segments of the genus 

 Illoenus. Suppose it could be po.ssible to give to two 

 different forms the same characteristics, (which is an im- 

 possibility) and we take Eichwald's given numbers, we 

 must give three species to the genus Asaphus, and five 

 to that of Ilia: nus. Now, Cryptonymus, which represents 



