Vol i907" IV ] Notes and News - 465 



species, fails to designate (see a) or to indicate (see b, d) its type, any 

 subsequent author may select the type, and such designation is not 

 subject to change. (Type by subsequent designation.) 

 •'The meaning of the expression 'select a type' is to be rigidly construed. 

 Mention of a species as an illustration or example of a genus does not con- 

 stitute a selection of a type. 



"III. Recommendations. — In selecting types by subsequent designa- 

 tion, authors will do well to govern themselves by the following 

 recommendations : 

 " (h) In case of Linnsean genera, select as type the most common or 

 the medicinal species. (Linnaean rule, 1 1751.) 



" (i) If a genus, without designated type, contains among its original 

 species one possessing as a specific or subspecific name, either as valid 

 name or synonym, a name which is virtually the same as the generic 

 name, or of the same origin or same meaning, preference should be 

 shown to that species in designating the type, unless such preference 

 is strongly contrainclicated by other factors. (Type by virtual tauto- 

 nomy). Examples: Bos taurus, Equus caballus, Oris aries, Scomber 

 scombrus, Sphccrostoma globiporum; contraindicated in Dipetalonema 

 (compare species Filaria dipetala, of which only one sex was described, 

 based upon one specimen and not studied in detail). 

 " (/) If the genus contains both exotic and nonexotic species from the 

 standpoint of the original author, the type should be selected from the 

 nonexotic species. 



" (fc) If some of the original species have later been classified in other 

 genera, preference should be shown to the species still remaining in the 

 original genus. (Type by elimination.) 



" (/) Species based upon sexually mature specimens should take 

 precedence over species based upon larval or immature forms. 

 "(to) Show preference to species bearing the name communis, vul- 

 garis, medicinalis, or officinalis. 



" (n) Show preference to best described, best figured, best known, 

 most easily obtainable species, or one of which a type specimen can 

 be obtained. 



" (o) Show preference to a species which belongs to a group containing 

 as large a number of the species as possible. (De Candolle's rule.) 

 " (p) In parasitic genera, select if possible a species which occurs in 

 man or some food animal, or in some very common and widespread 

 host species. 



" (q) All other things being equal, show preference to a species which 

 the author of the genus actually studied at or before the time he 

 proposed the genus. 



" (r) All other things being equal, page precedence should obtain in 

 selecting a type. 



1 " Si genus reception, secundum jus naturae et artis, in plura dirimi debet, turn 

 nomen antea commune manebit vulgatissimae et officinali plantae." 



