GASTROPODA. 1019 
Cewlocaulus.] 
Concerning the identity of the species just described and Hall’s Murchisonia major, we can only say 
that after as careful an investigation as was possible without having an opportunity of studying the orig- 
inal types, we are fairly well satisfied that our shells are really the same as the one figured by Hall. Very 
likely his original lot of specimens included other forms of these large shells, but if the present species is, 
as we believe, among them, then it would be well to retain the name major for it and throw out the 
others. This course is to be commended if only for the reason that it will greatly simplify matters in the 
way of synonomy. 
It is often asserted that H. major is but a large form of H. bellicincta, while Whiteaves would make 
it the same as Billings’ I. teretiformis. However, and providing that we have correctly identified these 
species, the totally different suture of H. major shows conclusively that it is not even closely related to 
either of the two other species mentioned. 
The unusual character of the sutural region, which is well shown in our fig. 7, is of itself sufficient 
to distinguish this shell from all associated gastropods. Casts are separated from those of H. trentonensis 
by their narrower apical angle (taking the whole shell into consideration), by the less uniform convexity 
of the whorls, and the rectangular instead of rounded junction of the upper and outer sides of the whorls. 
The last difference is very striking when transverse sections of the whorls are compared. The lower 
extremity of the mouth also is much less produced and therefore blunter. Casts of Lophospira augustina 
Billings sp., are sometimes found in the same layers with H. major, but the wider apical angle and 
obtusely angulated whorls of the former renders confusion in this case highly improbable. If perfect 
shells of these various species could be compared, we are convinced that the merest tyro in the science 
would separate them at once. 
Formation and locality —Though widely distributed, this species appears not to be abundant at any 
locality. It is restricted to the Trenton group, and in Minnesota occurs in both the Fusispira and Mac- 
lurea beds at Lime City, Stewartsville, Mantorville, Hader, and other localities. The original types were 
obtained in Wisconsin, and the species is said to occur at many points in that state. Good casts have 
been found in Pike county, Missouri. 
Collections—Geological and Natural History Survey of Minnesota; E. O. Ulrich. 
Museum Register, Nos. 7345, 7485, 7842. 
Genus CHILOCAULUS, @hlert. 
Murchisonia (part.) of LinDSTROM, BILLINGS, and other authors. 
Celocaulus (HHLERT (as subgenus of Murchisonia), 1888, Extr. Bull. Soc. d’Etud. Scientif. d’Angers, 
p. 20. 
For generic characters see page 959. The date of this genus should be 1888 
instead of 1887. 
This type of shells is not as closely related to Hormotoma as may appear on a 
hasty comparison. To the practised eye there is something peculiar about their 
general aspect that at once causes them to be set aside as a group by themselves. 
With few exceptions they are all very slender many-whorled shells, with a contin- 
uous narrow umbilical perforation, the inner lip straight and the lower angle of the 
aperture comparatively very little produced. The whorls are depressed, in two 
instances our (C. neglectus and C. barroisi Hhlert) probably not more than twelve in 
number, generally exceeding fifteen, and in some cases as many as thirty. The 
band in all observed cases is wide and flat and lies beneath the middle of the whorls 
of the spire. In at least some of the species a considerable number of the apical 
whorls are filled with an organic deposit. 
