LOWER CRETACEOUS FOSSILS — ETHERIDGE. 139 



define Crioceras, but from developmental facts brought forward 

 discussed the propriety of subdividing the genus. Glancing 

 through their figures I find their conception of the latter includes 

 — (a) close coiled forms (C. seeleyi); (b) the same with a shaft or 

 limb (C. urbani); and (c) open coiled forms (C. capricornu, C. 

 roemeri). 



In 1883(1) Dr. V. Uhlig restricted Crioceras 10 by removing 

 from it C. asterianum, D'Orb., and with Hamites depressus 

 establishing for them the genus Fidelia, 11 as a connecting link 

 with the Ammonite Lytoceras, Suess. Uhlig further removed 

 from Crioceras a group of species typified by C. puzosianum, 

 D Orb., of a more or less dwarfed habit, and a louse open 

 coil, as Lytoceras. 1 - The embryonal chamber in the last 

 named is followed by one, or one and a half, smooth whorls, 

 when costse are gradually acquired, with ;i limb and crozier. 

 "Uhlig, after a close study of the Cephalopoda of the Werns- 

 dotf beds, arrived at the conclusion that the major part of the 

 forms referred to as Crioceras or Ancyloceras were genetically 

 annexed to Hoplites, and that a generic distinction between the 

 spiral Crioceri and those of the Ancyloceras type was superfluous. 



In 1889 Mr. E Haug suggested a separation of Crioceras and 

 Ancyloceras based on the sculpture which he considered was much 

 stronger on the "dwelling chamber" (shaft and crozier) of Ancy- 

 loceras than on the spirally inrolled whorls " which in Crioceras 

 never appear to be the case'' 1:; ; he selected Ancyloceras mathero- 

 nianum, D'Orb., as the type of Ancyloceras, and included in it 

 both close and open-coiled shells 1 '; as an example of the former 

 is Scaphites coquandi, Math., and of the latter S. provinciate, 

 Math. The sculpture selected by Haug as typical of his defini- 

 tion of Ancyloceras consists of a uniform double row of tubercles 

 on the flanks and two rows of abdominal tubercles (i.e., one on 

 each side the median line of the venter) always on the crozier, 

 and sometimes on the spiral. 1 "' So far as I can understand his 

 meaning, Haug appears to regard all Crioceri as constantly 

 inrolled in a plane, bow-shaped, or spiral, in the latter case 

 with or without a crozier. 



l0 Uhlig— Denks. K. Akad. Wiss. Wien., xlvi., 2, p. 25S. 

 "Uhlig— Lor. fit., p. 202. The name Pictetia was subsequently (1S85) 

 proposed by C. Brongniart for a Neuropterous insect. 

 l2 Uhlig— Loc. cit., p. 260. 



i3 Haug— Beitrage Pal. Oster.-Ung. Orients, vii., 3 and 4, 1889, pp. 207 

 and 212. 



!i Haug — Loc. cit.. p. 214. 

 l5 Haug — Lor. cit., p. 214. 



