ORDER II AMMONOIDEA 587 
Cosmoceras, Waagen (Fig. 1227); Phricodoceras, gen. nov. Type P. (Amm.) 
Taylori, VOrb. sp.; Sigaloceras, gen. nov. Type S. (Amm.) calloviense, VOrb. sp. 
Middle Lias to Oxfordian. 
Family 28. Pedioceratidae. 
Young resemble Cosmoceratidae, but later 
the large single or imperfectly bifurcated 
costae are apt to cross the venter. Some- 
times all traces of tubercles are lost, but 
most forms possess until a late stage a row 
on the ventro-lateral angles, another in 
juxtaposition to this externally, and either 
two more or none inside these rows. 
Pedioceras, Gerh.; Douvilleiceras, 
Gross. (Fig. 1228); Steweroceras, Cossm. 
(Odontoceras, Steuer); Diadochoceras, gen. 
2 ’ lve e ae Cosmoceras ornatum, Sowb. sp. Callovian (Ornaten- 
nov. Type D. (Amm.) nodosocostatum, thon); Gammelshausen, Wtirtembers. 
Orb. sp. Cretaceous. 
Family 29. Anisoceratidae. Uncoiled shells with only two rows of tubercles 
on either side, and costae 
similar to those of preceding 
family. The adult Anzso- 
ceras has a Helicoceran 
aspect, develops a_ long, 
eccentric Toxoceras-likevolu- 
tion in the gerontic stage, 
and terminates with a retro- 
versal bend or crook, 
Anisoceras, Pict. ; Tono- 
ceras, gen. nov.- Type T. 


Fic. 1228. 
Douvilleiceras mamillare, Schloth. sp. Gault ; Macheroménil, Ardennes. 
(Ancyl.) Duvalianum, Orb. sp.; Hyphantoceras, gen. noy. 
Type H. (Heteroc.) Roissyanwm, Schliit. sp. Cretaceous. 
Family 30, Turrilitidae. Turriliticones having 
more or less angulated volutions, with two rows of 
tubercles on either side of the median line of the venter. 
Shells close-coiled from the earliest stage, or with only a 
slight eccentric deviation in old age; often partially 
costate, and sometimes with only three rows of tubercles 
in older stages. Aperture much elongated transversely, 
and contracted in extreme age of Turrilites by ingrowth Fic. 1229. 
of the right side. Costae continuous across the venter | Turrilites catenatus, d’Ord. 
or interrupted by a smooth zone, and either single or ie nee ical Tee 
divided between the rows of tubercles. ia 
Turrilites, Lam. (Fig. 1229); Ostlingoceras, gen. nov. Type 0. (Turr.) Puzosianwn, 
(Orb. sp. Cretaceous. ; 
Family 31. Ancyloceratidae. Includes only such forms usually assigned to 

