36 ORDOVICIAN AND SILURIAN BBLLBROPHONTACEA. 



flattened towards mouth. Slit-band wide, slightly sunken between raised edges. 

 Surface of dorsum ornamented with fine revolving lines, about 10 on each side 

 of slit-band, adjoining which they are more crowded, and all decussated by very 

 fine transverse striae ; umbilical slopes smooth ? 



Dimensions. — . i ii 



Height . . . about 10 mm. . about 13 mm. 



Thickness . . . ., 8 ,, . ,, 10 „ 



Horizon. — Bala Series. 

 ■Localities. — Onny River, Shropshire; Tyrone. 



IlemarJiS. — There are four specimens of this species (Nos. 28006, 28007), three 

 on one piece of rock, in the Jermyn Street Museum, from the Onny River ; and 

 these are the shells, so far as can be ascertained, which Salter described in 1854 

 {loc. fit.) as Bt'lleyojihoit. (Bacanla) snlcatintis, Emmons?, suggesting the name 

 liugiialis if they should turn out to be a different species. The specific diagnosis 

 was given in the following words: "B. uncialis et ultra, couvolutus, anfractibus a 

 dorso convexiusculo depressis, striatis. Carina lata, plana (sublasvis?), niarginata, 

 vix elevata. Striae concentricse fortes, circiter 10 (ad carinam ssepissime inter- 

 striatge et in ajtate plurima3), a lineis crebris valde reflexis undigue decussatse. 

 Apertura lata, expansa, semi profundo. This very beautiful shell differs from 

 B. sulcatinus, as figured by Hall, in having regular ribs towards the angular edge, 

 which become interlined and form a broad band of close stria3 as the shell grows 

 older. The umbilical face, too, is free from ribs, which I have some reason to 

 think is not the case with B. sulcatinus. The strise, too, on that shell appear 

 to meet at a very much more obtuse angle than in ours. It should be called 

 B. lingualis if the above characters are sufficient to separate it. It must have 

 been a very thin shell." Salter adds (p. 68) that this shell is also found in 

 Tyrone.^ 



This Onny River species cannot be referred to Bncnnia as now interpreted 

 and restricted, of which genus B. sulcafina is the type, and it is obviously 

 referable to Kokenospira. The species from the Redhill Beds described by me in 

 1906 as Bellerophon {Bucanop.ns) secnndus^ may be identical (see p. 39). 



Bucan[i]ella esthona Koken,^ which Ulrich and Scofield have chosen as the 

 type of their genus Kokenia, bears a considerable resemblance to Salter's species, 

 and K. costalis, Ulr. & Scof.,* is also closely allied. Probably B. lateralis, Eichw.,'^ 

 is also allied. 



1 'Cat. Camb. Silur. Foss. Mus. Pract. Geol. Lond.' (1878), p. 57. 



2 Eeed, ' Geol. Mag.' [5], vol. iii (1906), p. 366, pi. xx, figs. 15, 15 a. 



'^ Koken, ' Neues Jahrb. f. Miner.,' suppl. vol. \i (1889), p. 389, pi. xiii, figs. 1,1a. 

 ■* Ulricli and Seofield, op. cit., p. 882, pi. Ixiv, figs. 46 — 49. 



sEichwald, ' Letli. Eoss.,' vol. i, pt. ii (1860), p. 1083, pi. xl, fig. 28; Kokeu, ' Gastrop. Bait. 

 Uiitersilurs,' p. 127. 



