GASTROPODA. 1037 
Eccyliomphalus subrotundus.] 
of Orthis. Also that the inner whorl is cut off from the remainder of the spiral tube by imperforate 
concave partitions. 
Formation and localityi—Stones River group, Minneapolis, Minnesota; Beloit, Wisconsin; La Salle, 
Illinois; and Lebanon, Tennessee. 
Collection.—E. O. Ulrich. 
EccyLIoMPHALUS SUBROTUNDUS, ”. Sp. 
PLATE LXXV, FIGS. 17 and 16. 
This shell differs from #. undulatus in that it forms littte 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, and 
has the ridge on the inner side placed lower. The ridge is also more sharply defined and thinner. ZH. 
intortus Billings, of the Point Lévis limestone in Canada, is in many respects a similar shell, yet is more 
closely involute, expands more rapidly, and is without the ridge on the inner side. 
Formation and locality.—Fusispira bed of the Trenton group, Wykoff, Minnesota. 
Collection.—H. O. Ulrich. 
EccyLIOMPHALUS conTiauuS, n. sp. (Ulrich.) 
PLATE LXXYV, FIGS, 48—52. 
Shell 12 to 30 mm. in diameter; 7 to 16 mm. in hight, consisting of three or four rapidly enlarging 
contiguous whorls, coiled so as to leave a deep umbilicus in which from a third to a half of each of the 
_inner whorls is visible; whorls subovate 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 irrezular and coarse, parallel with the edge of the mouth 
That the whorls in this shell are contiguous, we cannot consider as a serious objection to classifying 
it with EHecyliomphalus. A sufficient justification of our arrangement is found in Lindstrém’s Huomphalus 
gotlandicus which clearly belongs to this genus, and in which the whorls may be quite indifferently totally 
evolute or closely joined.* 
Formation and locality —Lower part of the Stones River group, Murfreesboro, Tennessee. 
Collections. —Prof. J. M. Safford; E. O. Ulrich. 
Family MACLURIIDA, Woodward. 
We have 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 Huomphalide. About twenty-four American species have 
been described, and all of these, though exhibiting considerable variation, have 
heretofore been placed into the single genus Maclurea. 
Considering the great differences exhibited by the opercula of some of these 
species, it seems to us that their arrangement in one genus can only be justified as 
*There may be some doubt concerning the specific identity of all the various forms referred by Lindstrém to his 
Euomphalus gotlandicus, but there can be none when it comes to their generic alliances. 
