62 GANOID riSHES OF THE CARBONIFEROUS FORiMATION. 



tion of the fossil. I fear, therefore, that there is some mistake as to this specimen 

 having been derived from the Carboniferous Limestone of Vise, but in any case it does not 

 belong to the present species. It is also clear that Giebel has been mistaken in his 

 determination of the specimen from Lobejiin which he has figured as " Palaoniscus 

 striolatus," and which I have exanuned in the Geological Museum of the University of 

 Halle. 



So far, then, as I have been able to ascertain with certainty Eloniehtht/s striolatus has 

 as yet occurred only in strata of Lower Carboniferous age. 



The publication of this Monograph, interrupted since 1877, is now resumed in 1901. During 

 that period of twenty-three years our knowledge of the Ganoid fish-fauna of the British Carboniferous 

 rocks has immensely increased, as was only to be expected. Several new genera as well as many new 

 species have occurred, which may now be described consecutively without having to go back on the 

 subject by means of extensive " supplements." One other result of the additional experience which 

 the study of greatly increased material has brought with it is, that I have come to look upon many 

 forms, which I previously lield to be distinct species, as only constituting well-marked varieties, or in 

 some cases the immature stages of other species. The immediate relegation of these to their proper 

 places, without tlie use of supplements, will also be a decided advantage to the work as now 

 resumed. 



So fai', however, as the anatomical features of the family at present under consideration are 

 concerned, a short appendix will be necessary, as many additional details have been discovered since 

 the section on tlie Structure of the Palfeoniscida? was written. These will be noticed meanwiiile in 

 the descriptions of the genera and species in which they have been observed. But there is one point of 

 bone-nomenclature to which I must at present make special allusion. It is this, — that I have for 

 some years back regarded the quadrangular plate marked " interoperculum " in my previous figures as 

 the true suhoperculum, and as such it will be henceforth described and lettered. On the other hand, 

 the small plate above its antero-superior angle seen in some genera, such as Elonichthi/s, and whicli 

 Rhabdolepis (PI. II, fig. 6, s. o.) extends back so as to separate the operculum from the sub- 

 operculum, I now consider as merely an accessory plate, though formerly I lettered it as 

 " suhoperculum." * 



4 «. Elonichihys RoBisoNi, y/2(^(^<?r/, sp. Plate VH, figs. 4 — 15; Flates VIII — XI; 



Plate XIV, figs. 4—8 ; Plate XV. 



Paljeoniscus Kobisoni, Hibhert. Trans. Koy. Soc. Edinb., vol. xiii, p. 191, pi. \i, 



figs. G, 7 ; pi. vii, figs. 1—3, 1835. 



— — Agassiz. Poiss. Fosa., vol. ii, pt. i, ]>. 88; Atlas, vol. ii, 



tab. \a, figs. 1, 2, 1835. 



— — Morris. Cat. Brit. Poss., p. 337, 1854. 



1 E. H. Traquair, " Notes on Chondrosteus acipenseroicJes, Agassiz," ' Geol. Mag.,' dec. 3, 

 vol. iv, 1887, p. 25'i, foot-note. " List of the Fossil Dipnoi and Ganoidei of Fife and the Lothians," 

 ' Proc. Roy. Soc. Edinb.,' 1889-90, p. 397. See also Dr. A. Smith Woodward (' Cat. Poss. Fishes 

 British Mus.,' pt. ii, p. 487), who considers what I have above called an "accessory plate" to be a 

 true interopercidum. 



