64 Proceedings of the Royal Physical Society. 



stead of a fold. Under the name of Strohccus^ De Koninck 

 has proposed a new genus for these shells, on the ground that 

 Elenclms (M'Coy) is not equivalent to Elenchus (Humphrey), 

 the originator of the latter name. 



A number of small shells occurring in our Carboniferous 

 rocks have from time to time been referred to Turlo and 

 Trochus. It has been manifest for many years to Palaeon- 

 tologists in general, that the shells in question, such as Turho 

 hiserialis (Phillips), Trochus hiserixttus (Phill.), T. coniformis 

 (De Kon.), and T. lepidus (De Kon.), have no direct relation 

 with the genera named. The absence of good material has 

 prevented some, whilst a determination not to interfere with 

 accepted names has deterred others from dealing with these 

 troublesome shells. At last, however, Professor de Koninck 

 has grappled the difficult subject in his recent work, and 

 proposed several new genera for their reception. 



I have for some time been of opinion that Trochus hiser- 

 ratus should be placed in Meek and Worthen's genus Micro- 

 doma.-f The whorls are ornamented with close spiral line, 

 there is no true band, and the lip does not appear to be 

 sinuate. It is much satisfaction to find that De Koninck 

 has placed it in this genus. | 



The Trochus coniformis (De Kon.), both a Belgian and 

 Scotch shell, is referred to one of the new genera, under the 

 name of Flcmingia,^ allied to Trochus. Another species, 

 Trochus lepidus (De Kon.), now becomes Ticrhonellincc, II a 

 genus again resembling the living Trochus, but with a very 

 large umbilicus. Lastly, for Turho hiserialis and two other 

 species, the name Turhonitella^ is proposed, a small turbinate 

 univalve, either smooth or tuberculated, and with a depressed 

 callosity on the inner lip. I had already expressed my belief 

 that a distinct genus was required for the reception of this 

 shell.** To complete the genera placed by De Koninck in the 

 Turbinidse, must be mentioned Aclisina.ff In this it is pro- 

 posed to place, amongst others, a small elongated spiral with 



* Gasteropodes, p. 25. 



t Proc. Acad. Nat, Sciences, Philadelphia, 1866. X Gasteropodes, p. 104. 



§ Ibicl., p. 97. II Ibid., p. 76. H Ibid., p. 72. 



** Annals Nat. Hist., 1880, v., p. 485. ft Loc. cit, p. 86. 



