﻿302 A.RTHRODIRA.. 



Dinichthys ? precursor, J. S. Newberry, Palaeoz. Fishes X. America 

 (1889), p. 51, pi. xli. — Corniferous Limestone (Lower 

 Devonian) ; Sylvania, Ohio. [Median dorsal shield.] 



Dinichthys ringuebergi, J. S. Newberry, op. cit. (1889), p. 60 : 

 Dinichthys minor, E. N. S. Ringueberg (non Newberry), 

 Amer. Journ. Sci. [3] vol. xxvii. (1884), p. 476, woodc. 

 figs. 1, 2. — Portage Group (Lower Carboniferous); Stur- 

 geon Point, New York. [Median dorsal shield.] 



Dinichthys terrelli, J. S. Newberry, Rep. Geol. Surv. Ohio, vol. i. 

 pt. ii. (1873), p. 322, and ibid, vol.ii. pt. ii. (1875), p. 27, 

 charts v., vi., and Palaeoz. Pishes N. America (1889), 

 pi. iv. figs. 1, 2 : D. hertzeri, J. S. Newberry {errore), Rep. 

 Geol. Surv. Ohio, vol. i. pt. ii. pis. xxxii.-xxxiv. — Huron 

 Shale ; Lorain Co., Ohio. [Head, with jaws, &c. This is 

 the largest known species, the transverse measurement of 

 the occipital region of the cranium being 0*95.] 



(?) Dinichthys tuberculatus, J. S. Newberry, Trans. New York 

 Acad. Sci. vol. vii. (1888), p. 179, and op. cit. (1889), 

 p. 98, pi. xxxii. fig. 3. — Chemung Group (Upper Devo- 

 nian) ; Warren, Pennsylvania, and Ohio. Also recorded 

 from Psammite de Condroz, near Liege, Belgium. [Por- 

 tions of tuberculated plates.] 



Genus TITANICHTHYS, Newberry. 

 [Trans. New York Acad. Sci. vol. v. 1885, p. 27.] 



Plates of head and trunk [except plastron, which is unknown] 

 resembling those of Dinichthys, but relatively thinner. Mandibular 

 rami without denticulations, long and slender, grooved in the ante- 

 rior portion of the oral margin, as if for a horny sheath, and some- 

 what turned upwards at the symphysis. 



The two known species of this genus attain a size even greater 

 than those of Dinichthys, the cranium measuring not less than 1-25 

 across the occipital region. They are described as follows, but are 

 not represented in the Collection : — 



Titanichthys agassizi, J. S. Newberry, Trans. New York Acad. 

 Sci. vol. v. (1885), p. 27, and Palaeoz. Fishes N. America 

 (Mon. U. S. Geol. Surv. no. xvi. 1889), p. 133, pi. i. figs. 

 1, 2, pi. ii. figs. 1, 2, pi. iv. fig. 4. — Cleveland Shale 

 (Lower Carboniferous); Lorain Co., Ohio. [The type 

 species. Head ; Mils. Comp. Zoology, Cambridge, Mass.] 



Titanichthys clarhi, J. S. Newberry, Trans. New York Acad. Sci. 

 vol. vi. (1887), p. 164, and Palaeoz. Fishes N. America 



