184 NEW YORK STATE MUSEUM 



these organisms, they may thereby also do a service. Before, 

 then, proceeding to a special account of these bodies I shall 

 undertake a brief historical exordium. Without this one dare 

 not employ the outstanding generic names. 



The term, Agelacrinus, employed even by iso late and 

 accomplished an author as Bather^ is not entitled to the respect 

 it has received. It has been long in use, but usage can not be 

 granted to play as important a part in the construction of a 

 scientific nomenclature as in the building of a language. Agela- 

 crinites was the original form of the word as employed by 

 Vanuxem for his unique fossil, A. h a mi 1 1 o n e ns i s.^ A 

 later well intentioned writer conceived it wise to drop the ites 

 and add the ws, as was then doing with names of crinoidal genera 

 which had been terminated with the former syllables. Not only 

 ai-e the author's rights conserved, but the differentials of the 

 genus are indicated by the retention of the original word. 

 Various distinguished authors, Meek and Worthen, Billings and 

 Jaekel have eschewed the substitute, but the wrong word is still 

 in active service. 



Meek and Worthen^ were the first to recognize by name what 

 they believed to be a generic difference between the middle 

 Devonic Agelacrinites and the species from the Siluric and 

 lower Carbonic which were all being included under that name; 

 a difference in the character of the plates, imbricating in the lat- 

 ter and juxtaposed in the former; and in the direction of the arms, 

 two of the five being dextral (solar^) in the former, and but 

 one dextral in the latter. They proposed to distinguish the latter 

 by the term, Lepidodiscus, and, as this name was employed 

 lirst in connection with their species, Ag. (Lep.)squamosus 

 of the Keokuk limestone, we must assume this to be the type 

 species of that proposed division. Thus restricted it is clear that 



' Lankester's Treatise on zoology. 1900. pt 3. 



2 Geol. N. Y. 3cl geol. district. 1842. p. 158, Og. on p. 306. 



» Geol. 8ur. 111. 1873. 5:513. 



♦ Jaekel proposes to distinguish the rays In these bodies according to their direction by com- 

 paring them to the apparent motion of the sun or the course of the hands of a clock. Thus right 

 under to left and over to right (dextral) is solar, the opposite direction (sinistral) corUrasolar. The 

 terms are helpful and we have here employed them. 



