GASTROPODA. 1 (|; " 



...mplialu* iubt..lun.lii- ) 



hi*. Alw thai (If inn. i whorl i- cut off fmm the rfin.im.1. r -,t the spiral tube by Important* 

 concave partition*. 



Formation and locality. StooM River group, Minneapolis, Minnesota; Belolt, Wisconsin: La Sal It, 

 Illtm.lv and LHwinon. TCDDC 



CbO*d*m.-K. O. Urlrh. 



EoCYUOMPHAUm SOBROTt'NDUS, M. gf. 



I'l.ATK I \\v I I..- IT and Ik. 



This shell dlffrr- from . undufatujr to that It forms little more than a single volution, that the shell 

 expands more slowly, that It Is almost circular In cross-section, that It Is coiled In the same plane, ami 

 has the ridge on the Inner side placed lower. The ridge Is also more sharply defined and thinner. E. 

 n,r.. .-.'., Hillings, of th.- I'.. mi \. \.- limestone In Canada, Is In many respects a similar chell, yet Is more 

 closely Involute, expands more rapidly, and Is without the ridge on the Inner side. 



formation and locality. - FiHlgptra be1 of the Trenton group, Wykoff, Minnesota. 

 OWtortton.-E. O. Ulrlcb. 



EOCYLIOMPHALUS OONTIOUD8, M. 8p. (Ulrtch.) 

 PLATE LXXV, 



Shell 12 to 30 mm. In diameter ; 7 to 16 mm. In night, consisting of three or four rapidly enlarging 

 whorls, colled so as to leave a deep umbilicus In which from a third to a half of each of the 

 Inner whorls Is visible; whorls aubovate In section, higher than wide, somewhat narrowly rounded In the 

 outer half of the upper surface. On the upper side the Inner whorls may be sunken slightly beneath or 

 raised above the level of the last; Innermost whorl with a free termination. Mouth obliquely subovate, 

 the margin rather deeply notched above, broadly curved forward on the outer side and gently sinuate 

 below. Surface markings somewhat Irregular and coarse, parallel with the edge of the mouth 



That the whorl* In this shell are contiguous, we cannot consider as a serious objection to classifying 

 It with Kcryliomphalu*. A sufficient justification of our arrangement Is found In LlndstrOm'n Euomphalut 

 yotlandifia which clearly, belongs to this genus, and In which the whorls may be quite Indifferently totally 

 evolute or closely joined.* 



Farmalwn and locality. --Lower part of the Stones River group, Murfreesboro, Tennessee. 

 CWfcetioiu.-Prof. J. M. Safford ; E. O. Ulrlch. 



Family MACLURIID^, Woodward. 



We hare not been able to satisfy ourselves that this is a valid family and its 

 acceptance here is chiefly in deference to the views of previous authors. We are, 

 however, convinced that the natural affinities of the majority of the types usually 

 referred here are with the Euomph<tli(l<r. About twenty-four American species have 

 been described, and all of these, though exhibiting considerable variation, have 

 heretofore been placed into the single genus M-irlurra. 



Considering the great differences exhibited by the opereula of some of these 

 species, it seems to us that their arrangement in one genus can only be justified as 



There mar b* come doubt eoaevrnlnc the .pecllr Identity of all the rrl.,u. form* f*f*rr*d by Llnditmm to bU 

 MptahK tUttmHmi. bat tkcra caa be DOM wbo It com*, h. their ttatric allluew. 



