﻿458 



Remele, sp. Ang. et Lindstrom, and Facilituites ? Muellaueri, sp. 

 Devvitz. This last has the ventral saddles and approximately quad- 

 ragonal form of this genus. The sutures also have dorsal saddles 

 and the siphuncle is small and centren. There is a slight contact 

 furrow in the coiled volutions, which is still retained, but shows to a 

 less degree in the free part of the whorl as figured by Dewitz, and 

 the dorsal part of the aperture is flat, not concave. The living 

 chamber was evidently entirely free in these two species when full 

 grown, since in the figures by Angelin and Lindstrom and by 

 Dewitz this is shown. The umbilical perforation in Muellaueri is 

 so much larger than in Decheni that I refer this species to this genus 

 with considerable doubt. The close-coiled volutions are only two 

 in number. 



TrocholUidce. 



This group was formerly included by the author under the family 

 name of Tainoceratidae, but was separated in Carboniferous Cepha- 

 lopods Fourth Ann. Rep. Geol. Surv. Texas, and is here placed 

 under its proper title. The shells are smooth, or with heavy trans- 

 verse ridges, which are really primitive costations, but are never 

 very prominent. The whorls are nephritic or depressed sub- 

 quadragonal or trapezoidal, the venter generally broader than the 

 dorsum, and the form is usually nautilian. The sutures as a rule 

 have broad and slight ventral lobes and lateral lobes. 



The siphuncle is dorsad of the centre. The genera are as follows : 

 Litoceras and Trocholitoceras confined to the Quebec faunas, 

 Schroederoceras and Trocholites found in both the Quebec faunas 

 and the Lower Silurian. 



Schroederoceras. 



This genus has been described by Schroeder and others as Dis- 

 coceras, and as having close affinity with Trocholites. 



The affinity with Discoceras is apparently close, but when one 

 considers the heavily costated shells of that genus and the younger 

 stages of the conch, it becomes obvious that the species having such 

 distinct characters and different modes of development cannot be 

 associated according to the mode of research adopted here. 



There are some species like Schroederoceras Eatoni and Eich- 

 wa/di, which approximate in the number and form of the whorls to 



