GASTROPODA. 1081 
Appendix.] 
markings, apertural slit and band. The line beneath the figure shows the form of the basal side of E. 
turbiniformis. 6, The band of the second to the last whorl of same specimen, with a small portion of the 
surface above and beneath it, x3. c, Portion of the flat under surface of another specimen of H. plani- 
basalis, x2, Showing the direction of the lines of growth and the revolving lines which cover nearly the 
whole of this surface. d, Similar portion of the under surface of #. turbiniformis, 2, showing very delicate 
lines of growth but no revolving lines. e, Small portion of slope of spire of same for comparison with fig b. 
The surface markings are appreciably different and the sculpture and section of the slit-band widely at 
variance in the two species. (This cut should have appeared on page 956.) 
Fia@. 12.—Several Carboniferous species of Trepospira. aandb, Two views of a perfect specimen of 
T. spherulata Conrad sp., showing the depressed apex, short slit, projecting upper lip and other features 
characterizing in part this genus and species. c, Inner whorls of another specimen of this species, X10, show- 
ing several changes which take place in the early development of theshell. Both specimens are from Spring- 
fleld, Illinois. dande, A small specimen of Z. convexa Ulrich, natural size and magnified, viewed so as to 
show the depth of the apertural sinus and slit and the depressed convex spire. f, The same specimen viewed 
from above. g, Another specimen, also x2, showing the under side. T. convewa is a new species, differing 
from the others in the gentle convexity of the upper side of the whorls. It is from the Lower Coal Meas- 
ures at Seville, Illinois. A, Lateral view, <2, of a specimen of T. illinoisensis Worthen sp., from Peoria, Illi- 
nois. (This cut should have appeared on page 957.) 
Errata for the chapter on Gastropoda. 
PAGE. 
819, 15th to 17th lines from top. As this chapter has taken more space than was expected, it is necessary 
to omit the classification and summary spoken of in those lines. 
846, 5th line from bottom, CU. subplanus. This species is well figured on plate LXI (figs. 40 to 44), but 
unfortunately its description was overlooked. 
847, add to last paragraph: For figures of Whitfield’s species see appendix, page 1080. 
871, 10th line from top, between third and fourth words insert inner. 
956, add to first paragraph: For figures of species of this genus see appendix, page 1080. 
957, add to second paragraph: For figures of this and other species of this genus see appendix, page 1081. 
960, 4th line from bottom, for ‘*‘ page ——” read page 951. 
978, 12th line from bottom, for ‘‘ LOPHOSPIRA MULTIGRUMA Miller” read LOPHOSPIRA TROPIDOPHORA 
Meck sp.; and to synonowmy of the species add: Plewrotomaria ( Scalites?) tropidophora MEEK, 1873, 
Pal. Ohio, vol. i, p. 154, pl. xm, figs. 6a, b. 
979, 6th line from bottom, add: (Not HALL.) 
982, 10th line from bottom, under LOPHOSPIRA SAFFORDI insert PLATE LXXII, FIGS. 49—51. 
995, 15th line from top, for ‘‘ Figs. 36—38” read FIGS. 35—88. 
995, 27th line from top, the shell referred to in the paragraph beginning with this line is illustrated on 
plate LXX XII by figures 42—44, and is there named Liospira modesta. 
