210 
ACTINOPTEKYGIT. 
P. 7437. Left splenial either of this or the preceding species ; 
Portlandian (zone of Ammonites gigas), Duingen, Harz. 
Purchased , 1895. 
Mesodon damoni, A. S. Woodward. 
1860. Pycnodus bucklcmdi, R. Damon {errore), Geol. W T eymouth, Suppl. 
pi. viii. fig. 9. 
1890. Mesodon, sp., Woodward & Sherborn, Catal. Brit. Foss. Verte- 
brata, p. 121. 
1890. Mesodon damoni, A. S. Woodward, Geol. Mag. [3] vol. vii. p. 158. 
1893. Mesodon damoni , A. S. Woodward, ibid. vol. x. pi. xvi. fig. 6. 
Type. Left splenial dentition ; British Museum. 
A large species, known only by the dentition of the lower jaw. 
Teeth rounded or closely arranged, smooth or very feebly rugose, 
without an apical pit. Teeth of principal series on splenial bone 
almost or quite twice as broad as long; teeth of the inner series 
considerably larger than any of the outer series, flanked within also 
by an irregular, incomplete row of small teeth ; those of the outer 
series arranged in four irregular rows, variable in size, but the 
innermost and outermost usually the largest. 
Form. Sf Loc. Portlandian: Dorsetshire. 
P. 6165. Left splenial bone, the type specimen ; Portland. 
Damon Coll. 
P. 6180. Right and left splenial dentition, partly fractured, in 
slab of limestone ; ITpway, near Weymouth. Damon Coll. 
P. 1642-3. Imperfect right and left splenials; near Weymouth. 
Egerton Coll. 
P. 3738. Right splenial; near Weymouth. Enniskillen Coll. 
P. 4678. Fragmentary left splenial; Ridgway near Weymouth. 
Presented by C. Westendarp , Esq., 1884. 
Mesodon gigas (Agassiz). 
1742. Dent de Dentato, L. Bourguet, Traite des Purifications, p. 78, 
pi. lvii, fig. 396. 
1833-44. Pycnodus gigas , L. Agassiz, Poiss. Foss. vol. ii. pt. i. p. 17, 
pt. ii. p. 191, pi. lxxi. fig. 13, pi. Ixxii. a. figs. 56-58. 
1839. Pycnodus gigas, F. A. Roemer, Verstein. Norddeutsch. Ooli- 
thengeb., Nachtr. p. 54. 
1860. Pycnodus gigas, F. J. Pictet, Rept. & Poiss. Foss. Jura Neu- 
chatelois, p. 46, pis. x., xi., pi. xviii. fig. 2. 
