416 General Notes. 
shell is larger, the apex more blunt, the greater obliquity of the 
volutions, and in their greatest convexity being at or below the centre. 
osition and locality, Rockford shales, Owens Grove (south 
exposure), Cerro Gordo county, Iowa. 
onema owenensis, n. sp.—Shell very large and robust, subco- 
niform; spire rather rapidly ascending, apex blunt. Volutions 
eight to ten or more, very oblique, strongly inflated, most prom- 
inently so below the centre, rounded. Suture deeply channeled; 
shell from two mm. to six mm. in thickness; aperture subovate. 
Surface apparently smooth. The depth of the suture in this species 
is very much greater than the suture in either the foregoing or fol- 
lowing species. Height of adult specimens from fourteen to six- 
teen and one-half centimetres ; diameter of body volution from four 
to five centimetres. This is, we believe, the largest species of the 
genus yet described. Position and locality, Rockford shales, 
Owens Grove (south exposure), Towa. 
oxonema crassum, n. sp.—Shell large, subconiform depressed, 
rapidly broadening from the blunt apex. Volutions from five to 
seven, slightly flattened or broadly rounded ; suture strongly chan- 
neled below; shell very thick ; surface apparently smooth ; aperture 
ovate. This species differs from L. gigantea in its more robust, 
depressed form, and the less convexity and obliquity of its volutions. 
Position and locality, Rockford Shales, Owens Grove (south 
exposure), Iowa. Quite a large number of specimens of each of the 
species described have been secured, and their specific differences 
are shown to be constant and well marked.—Clement L. Webster, 
Charles City, Iowa. 
Some Extinct SCLERODERMS.—In 1887, in the Memorie della 
Societa Italiana delle Scienze of Naples (3d series, v. 6, No. 4), 
Baron Achille de Zigno has published descriptions and illustrations 
of two very interesting Scleroderms from the Eocene beds of Italy. 
One of these is the Protobalistum imperiale of Massalongo, the other 
a previously unknown species considered to be congeneric with the 
ormer and named Protobalistum Omboni; both were obtained from 
the celebrated Mount Bolca beds. The most casual examination 
will convince one who has had much experience with recent fishes 
that the two species have little in common and belong to very dif- 
ferent genera if not families. Both are, however, important for the 
light they may throw on the genetic relations and former distribu- 
tion of the Scleroderms, but each owes its importance to a different 
reason. 
The generic description of Protobalistum given by Baron de 
Zigno is based on the assumption that there are certain characters 
1 Duc nuovi pesci fossile della famiglia dei Balistini scopertinel tef- 
reno eoceno del Veronese. (8 pp., 2 pl) 
