NOVEMBEK 10, 1905.] 



SCIENCE. 



599 



of these, is invalid and its type, D, becomes 

 the proper type of X. This is the simple 

 condition of the problem. But let A and G 

 be set off to form a new genus; C and D, an- 

 other. Let a new genus be formed which 

 would probably include B in it. Let still 

 another be framed which might possibly in-- 

 elude D. T^et it be further uncertain whether 

 A and B should be placed in different groups. 

 Let still another writer definitely connect the 

 old genus with A, while another uses it, not 

 for any of its constituents, but for some new 

 form probably congeneric with B, and you 

 have a not unusual statement of the problem. 



There is no way out of this .by the rule of 

 elimination. By accepting the first reviser 

 rule, itself subject to the Linnsean rule and 

 the rule of tautonomy, we may well fall back 

 on the rule of page precedence, and let the 

 rule of elimination be simply a recommenda- 

 tion to the first reviser, without direct validity 

 of its own. This is the position of the rule of 

 elimination in the new International Code. 



T give two concrete illustrations of the 

 difiiculties of the rule of elimination among 

 genera of fishes. 



The genus Clupanodon Lacepede, 1803, was 

 based on ' toothless herrings,' the chef de file 

 being Clupanodon thrissa. This species .as 

 described by Lacepede, is the Clupea thrissa 

 of Broussonnet, the American species, later 

 called oglinus by Le Sueur. This is, how- 

 ever, not the original Clupea thrissa of Lin- 

 naeus, 1758, which was based on the Clupea 

 thrissa of Osbeck, 1757, a Chinese species, 

 later called Clupea, nasus by Bloch, a species 

 of Konosirus. The second species of Lacepede, 

 nasicus, is the same as Clupea nasus oi Bloch. 

 The- third, pilchardus, is the Clupea pilchardus 

 of Linnaeus, a species of Sardinia^ which is 

 probably the same as Sardinella. The fourth 

 species of Lacepede, sinensis, is apparently the 

 species called later Clupea ilisha, and is prob- 

 ably not the original sinensis of Linnasus. It 

 is a species of Clupeonia or Harengula. The 

 fifth, africanus, is a species of Ilisha, and the 

 sixth, jussieui, is the original type of the 

 genus Clupeonia. 



Arranging these according to the modern 

 genera: 



1. thrissa. The type of Thrissa Rafinesque, 1815, 



the name given as a substitute for the hybrid 

 name Clupanodon. 



Chatoessus Cuvier, 1817, based on Lacepede's 

 thrissa, the generic name later transferred 

 by Valenciennes to punctatus, the thrissa of 

 Linnseus. 



Opisthonema Gill, 1863, based on thrissa of 

 Lacepede = oglinus of Le Sueur. 



Konosirus Jordan & Snyder, 1900, based on 

 punctatus Schlegel, which is a congener of 

 Glupea thrissa Linnseus (= Clupea nasus 

 Bloch) and not of Clupanodon thrissa Lace- 

 pfede, which is oglinus of Le Sueur. Most 

 writers unite Konosirus with Dorosoma 

 Rafinesque, 1829; but the two are probably 

 distinct. 



2. nasicus. This is the original thrissa of Le Sueur 



and is congeneric with Konosirus punctatus. 



3. pilcharus. This has never been made type of a 



genus. It is certainly congeneric with 

 Sardinia Poey, 1870, with Amblygaster 

 Bleeker, 1855, and I now think with Sardi- 

 nella Valenciennes, 1845. Most writers 

 (wrongly I think) unite all these with 

 Clupea Linnaeus, 1758. 



4. sinensis. This is referred by Valenciennes to 



Clupeonia Valenciennes, 1845; which genus is 

 probably identical with Harengula Valen- 

 ciennes, 1845, earlier page. Most writers (I 

 think wrongly) place it in Glupea. 



5. africanus. This is congeneric with the type of 



Ilisha Gray, 1836, and with that of Pellona 

 Valenciennes, 1845. It has never been taken 

 as type of a genus. 



6. jussieui. Type of Clupeonia Valenciennes, 



1845, apparently congeneric with types of 

 Harengula and Kowala of the same author 

 on earlier pages. Usually referred to Clupea. 



By the first ' reviser ' after Lacepede, 

 Rafinesque, 1815, Thrissa is substituted for 

 Clupanodon, and, Lacepede's thrissa is doubt- 

 less to be taken as Rafinesque's type. By the 

 next, Buchanan, 1822, ilisha (= sinensis Lac.) 

 is described as a new species of Clupanodon. 

 The genus Clupanodon then dropped out of 

 notice imtil revived by Dr. Jordan in 1882, by 

 a process of elimination for Clupeonia jussieui. 

 Later the same writer, by another process 

 of elimination, substituted Clupanodon for 

 Sardinia. Still later, by the same process 

 with further light, the newly defined genus 

 Konosirus, being congeneric with Clupanodon 



