PRINCIPLES OF TAXONOMY 



913 



generic names derived from the Latin are not uncommon. Names 

 compounded from the two languages are undesirable. The name 

 should always express some prominent character of the genus, as 

 Orthoceras, from the Greek 6p66<: (orthos), meaning straight, and 

 Ke/aas (ceras) , meaning horn, the essential form of the genus 

 being that of a straight horn. Names are, however, not always 

 chosen with such direct meaning, while not infrequently the deriva- 

 tion of the name is obscure or fanciful. Proper names are fre- 

 quently chosen for generic names, as Hyattella for a genus of 

 brachiopods, the name being given in honor of the great American 

 palaeontologist, the late Alpheus Hyatt. In the formation of such 

 names the original name is reduced to the genitive case, and the 

 termination is in a (a, ia, Ha, oia, cca, ella, etc.). When the original 

 name ends in v this letter is treated as a consonant and the termina- 

 tion is added. Example: from Gray we may derive Gra\ia, Gra\- 

 ella, Graysia, etc. In all cases the form of the word must be the 

 Latin form, the Latin equivalent of the original Greek being used. 

 The gender of the generic name is the same as in the language 

 from which it is derived. If the generic name is a compound of 

 two or more words, the terminal word determines the gender. 

 Thus, in Orthoceras, the terminal ccras is neuter in the Greek, and 

 hence all names ending in this manner are neuter. The same is 

 true of the words nana (thread), stoma' {mouth), and dcsma 

 (band), often employed as endings. Special uniform endings are 

 often employed in the naming of genera within certain classes, such 

 endings having reference to the class. Thus pora and phyllum are 

 the common terminations for corals, the former being used in the 

 poriferous corals, as Aiilopora, Syringopora, Tuhipora, etc., and 

 the latter in the septate corals, especially the Tetraseptata ; example : 

 Cyathophvlluin, Heterophyllum, etc. In graptolites the termination 

 graptus is common. In Cystoidea, Blastoidea, Crinoidea and Echi- 

 noidea the common terminations of the generic names are cystites, 

 hlastus, crinus, and echinus, respectively, though these are by no 

 means exclusively employed. Examples are : Pleurocystites, Crypto- 

 hlastus, Encrinus, Eucalypto crinus , etc., and Rho'echinus. In 

 Bryozoa trypa and pora are frequent endings ; example : Callotrypa, 

 Bythopora. In Cephalopoda ceras is the prevailing termination, as 

 in Orthoceras, Gephyroceras, Phylloceras, Lytoceras, etc.. though 

 in some orders of ammonites (e. g., Discocampyli) the termination 

 ites is the prevailing one; example: Ceratiies, Stephanites, etc. 

 Among Reptilia sanrus is a common termination ; example : Mosa- 

 saurus, Stegosaurus, etc., and names of fossil birds not infrequently 



