RHTZODONTTD.'E. 
349 
Archichthys, A. Hancock & T. Atthey, Ann. Mag. Nat. Hist. 
[4] yoL v. 1870, p. 268. 
Labyrinthodontosaurus, T. P. Barkas, Coal-Meas. Palseont. 1873, 
p. 75. 
An imperfectly known genus, comprising species of medium or 
large size. Teeth subulate, without longitudinal keel, more or less 
bent inwards, and often sigmoidalty curved ; outer face nearly or quite 
smooth, inner face with vertical striations. Vertebral centra in the 
form of thin discs, pierced by a large mesial foramen for the passage 
of the remnant of the notochord. Scales very thin and deeply imbri¬ 
cating ; inner surface with a median, antero-posteriorly elongated 
protuberance, and a hinder sector marked by small pits; exposed 
surface relatively small, ornamented with few, large, longitudinal 
furrows, somewhat radiating and occasionally branching. 
The clavicle and infraclavicle of this genus are identical in form 
with those of Rhizodus described above (pp. 345, PI. XII. figs. 3-6). 
Strepsodus sauroides (Binney). 
[Plate XVI. figs. 1, 2.] 
1841. Holoptychius sauroides, E. W. Binney, Trans. Manchester Geol. 
Soc. vol. i. p. 165, pi. v. fig. 77 
1844. Holoptychius sauroides, L. Agassiz, Poiss. Foss. vol. ii. pt. ii. 
p. 180 (name only). 
1844. Holoptychius garneri, L. Agassiz, ibid. p. 180 (name only). 
1864. Holoptychius sauroides, Kirkbv & Atthey, Trans. Tyneside Nat. 
Field Club, vol. vi. p. 234, pi. vi. figs. 5, 6. 
1866. Strepsodus, J. Young (ex Huxley, MS.), Quart. Journ. Geol. Soc. 
vol. sxii. p. 602, woodc. fig. 3. 
1866. Dendropty chius, J. Young (ex Huxley, MS.), ibid. p. 601, woodc. 
fig. 7. [Scale ; Museum of Practical Geology.] 
1869. Strepsodus, T. P. Barkas, Scientific Opinion, vol. i. p. 556. 
1872. Strepsodus sauroides, G. Lyon, Trans. Edinb. Geol, Soc. vol. ii. 
p. 125. 
1873. Labyrinthodontosaurus simmi, T. P. Barkas, Coal-Meas. Paleeont. 
pp. 75, 94, figs. 194, 223, 224. [Fragment of mandible ; T. P. 
Barkas Collection, Newcastle-upon-Tyne.] 
1873. Strepsodus, T. P. Barkas, ibid. p. 32, figs. 113-119. 
1875. Strepsodus sauroides, J. Ward, [Proc.] N. Staffs. Nat. Field Club, 
p. 232. 
1875. Rhizodus (. Holoptychius ) garneri, J. Ward, ibid. p. 233, fig. 4. 
[Scale ; J. Ward Collection, Longton.] 
1875. (Dendroptychius, J. Ward, ibid. p. 233. 
1876. Strepsodus, W. J. Barkas, Monthly Rev. Dental Surgery, vol. iv. 
pp. 481, 529, figs, lxxxvi.-lxxxviii. 
