CESTRACIONTIDJE. 
229 
Venustoclus tenuicristatus, St. John & Worthen, op. cit. vol. vi. 
p. 348, pi. ix. figs. 19-24.—Keokuk Limestone; Illinois, 
Iowa, and Missouri. 
Venustodus variabilis, St. John & Worthen, op. cit. vol. vi. p. 346, 
pi. ix. figs. 7-14.—Burlington Limestone; Illinois and 
Iowa. 
(?) Cranodus zonatus, H. Trautschold, Nouv. He'm. Soe. Imp. 
Hat. Moscou, vol. xiv. (1879), p. 54, pi. vii. fig. 4.—Car¬ 
boniferous Limestone; Government of Moscow, Russia. 
(?) Tomodus argutus, H. Trautschold, tom. cit. p. 55, pi. vii. fig. 8 : 
Oxytomodus argutus, U. Trautschold, Bull. Soc. Imp. Nat. 
Moscou, 1880, pt. ii. p. 140.—Carboniferous Limestone; 
Government of Moscow, Russia. 
Other anterior teeth of Cochliodonts, from the Lower Car¬ 
boniferous of Russia, have also been described by Semenow & Moller, 
Bull. Acad. Imp. Sci. St. Petersb. vol. vii. (1864), p. 234, pi. i. 
figs. 1-8, 10. 
To the Cochliodontidse also may possibly be assigned the small 
prehensile teeth described under the following names:— 
PeripJectroclus compressus , St. John & AA or then, Pal. Illinois, 
vol. vi. (1875), p. 326, pi. viii. fig. 26.—St. Louis Lime¬ 
stone ; Illinois. 
Periplectrodus eaapansus , St. John & Worthen, tom. cit. p. 327, 
pi. viii. fig. 27.—Chester Limestone; Illinois. 
Periplecirodus warreni , St. John & Worthen, tom. cit. p. 325, 
pi. viii. fig. 25.—Burlington Limestone; Iowa. 
A single undetermined tooth from the Pliocene of Tuscany, 
certainly not Cochliodont, is described under the name of Helodus 
brugnonci by R. Lawley, Nuovi Studi sopra ai Pesci, etc., Colline 
Toscane (1876), p. 83; and an equally doubtful fossil from the 
Rhaetic of Stuttgart is named CJiomatoclus sphenodiscus , Plien., in 
Meyer & Plieninger’s Beitr. Pal. Wiirttembergs (1844), p. 55. 
Family CESTRACIONTLDiE. 
Dorsal fins each armed with a spine, the first opposite to the 
space between the pectoral and pelvic fins. Teeth mostly obtuse, 
never fused into continuous plates : several series simultaneously in 
function. 
No distinctive characteristics of value having yet been discoverer!, 
the so-called OEODONTinas and Hybodontol® are included in this 
family. 
