136 G. LINDSTROM, ON THE SILURIAN GASTROPODA AND PTEROPODA OF GOTLAND. 



are Silm-iau, have a slit in the h)\vei- edge of the exterior lip, much more shallow than 

 that of the Pleurotomarida; and nearly alike that in Pleurotoma and also in Turriteila'). 

 Durino- the growth this slit is never chaiijjod into a real slit band as in the Pleuroto- 



Oct <-> 



niari(la\ at the highest there is a narrow ridge, where the lines of growth are curved 

 backwards. When we see how niollusca, in other respects dissimilar, are provided with 

 this slit in tlieir shell, it is indeed very questionable whether the Loxoneraata only on 

 tiiat ground are so luiarly related to the genus Euoniphalus as to be included in the 

 same family as here proposed. There may, however, be added the similarity in the 

 consolidated apex, and they may thus, at least provisionally, be regarded as related 

 and Loxonema in a certain way to hold the same position to Euoraphalus as Murchi- 

 sonia holds to Pleurotomaria. 



Gen. EUOMPHALUS Sowerby p. p. 



1814 Fjuomplitthis Sow. p. p. Mineral Condi. I, 97. 



18.3;J Jiifi-ontia V>¥.?.\\^\'^fi p. p. Descr. Coqu. Coss. dcs fnvirons tie Paris, 221. 



1815.5 Schi:oKtoma Bronn Lethfea Geogn. Ed. 1, 9.5. 



184.3 Ecri/liomplinlus PoRTi.ocK p. p. Report (ieol. of Londonderry, 411. 



Shdl discoid iritli contiguous or disjointed lohorls; on the apical side of the aperture 

 a shaUov and obtuse slit or sinus is situated, the traces of which are seen on the whorls 

 as a more or less elevated rid(/e, toicards ichich the lines of growth are turning their api- 

 cal angle. The apex of the shell is filled with a solid calcareous deposition of organic 

 origin and is often subdivided through transverse diapliragms. 



After the detailed expositions of the affinities of this genus as given by De Ko- 

 NiNCK in his latest grand work and by Stoliczka^), Waagen') and Etiiekidge .ir'') only 

 a few remarks need be added, chiefly to show the standing point in this question of 

 J. Sowerby and Deshayes, the conchologists who have most essentially influenced the 

 opinion of others. 



When James Sowerby in February 1814 published his new genus Euomphalns 

 in M IX of the Mineral Conchology p. 97, he founded it on such species as Euomph. 

 pentangulatus, catillus and nodosus, all provided with the small notch in the corner of 

 the aperture on the apical side and a ridge in connection with it on the surface of the 

 whorls. But already in April the same year he joined with them in that very genus 

 others as E. discors, rugosus etc., Avhich do not share in the peculiarity of conforma- 

 tion, distinctive of the former. Conse{piently, when we are to fi.x the characters of 

 Eiiomphalus it must be in the original conception of its author. Next, the opinions of 

 Deshayes are of great importance, as most of th(> subsequent authors seem to have fol- 

 lowed him. In 1830'') he did not accept Euoraphalus as an independent genus, but 



') BooGE Watson Mollnsca of the Challenger Exp. in .loiirn. Linn. Soc., Zoology, vol. 1.5, p. 220. 



-) PaliBontologia Indioa V, p. 247. 



•0 Pal. Ind. XIII p. 8G. 



*) Ann. mag. N. II. .5tli Srr. vol. .5, p. 480. 



'-•) Eucyel. Method., Hist. Nat. d. Vers, vol. II p. 162. 



