236 
SIRENOIDEI. 
is given by C. H. Pander 1 and R. H. Traquair 2 ; and all the known 
species are of small size. 
Dipterus Valenciennes!,, Sedgwick & Murchison. 
1828. Dipterus valenciennesii, A. Sedgwick & R. I. Murchison, Trans. 
Geol. Soc. [2] vol. iii. p. 143, pi. xvi. figs. 1-3. 
1828. Dipterus macropygopterus, Sedgwick & Murchison, ibid. p. 143, 
pi. xv. figs. 1-3. [Mus. Geological Society of London.] 
1828. Dipterus brackypygopterus, Sedgwick & Murchison, ibid. p. 143, 
pi. xvii. figs. 1-3. 
1833. Catopterus analis, L. Agassiz, Poiss. Foss. vol. ii. pt. i. p. 3. 
1835. Dipterus macrolepidotus, L. Agassiz, ibid. p. 115, pi. ii. figs. 1-3, 
pi. ii. a. figs. 1-5. 
1841. Dipterus, H. Miller, Old Red Sandstone, p. 79, pi. v. fig. 1. 
1844. Polypkractus platycephalus, L. Agassiz, Poiss. Foss. V. G. R. 
pp. 5, 29, pi. xxvii. fig. 1, pi. xxxi. fig. 5. [Cranial shield ; British 
Museum.] 
1844. Megalichthys prisons, L. Agassiz, Poiss. Foss. vol. i. p. xxxiv 
(name only). 
1849. Dipterus, H. Miller, Footprints of the Creator, p. 59, figs. 18-22. 
1855. Dipterus brackypygopterus, D. macropygopterus, and D. valen¬ 
ciennesii, F. M‘Coy, Brit. Palseoz. Foss. p. 592. 
1858. Dipterus valenciennesii, C. II. Pander, Ctenodipt. devon. Syst. 
p. 6, pi. i. figs. 1-4, 8, pi. ii. figs. 1, 6, 7. 
1858. Dipterus platycephalus, C. H. Pander, ibid. p. 7, pi. i. fig. 5, pi. ii. 
figs. 2, 9, pi. iii., pi. iv. figs. 23, 27, pi. v. figs. 15-19. pi. vii. tigs. 
5, 11. 
18bl. Dipterus, I. II. Huxley, Figs. & Descrips. Brit. Organic Remains 
(Mem. Geol. Surv.), dec. x. p. 14, fig. 10 , woodc. 
18/1. Dipterus, A. Gunther, Phil. Trans, p. 556, pi. xxxiv. fig. 4. 
1878. Dipterus, R. II. Traquair, Ann. Mag. Nat. Hist. [5] vol. ii. p. 1 
pi. iii. figs. 1-4. 
1888, Dipterus valenciennesii, R. H. Traquair, Geol. Mag. [3] vol v 
p. 507. 
Type. Imperfect fishes ; Geological Society of London. 
The type species, attaining a length of not less than 0-4. Head 
with opercular apparatus occupying somewhat more than one fifth 
of the total length ; cranial shield very slightly tapering forwards, 
its maximum breadth at the occiput equalling about § its total length, 
and the snout abruptly truncated, with rounded lateral angles ; 
operculum trapezoidal, with slightly convex borders, as deep as 
broad ; tuberculations of dental plates large, well separated, laterally 
1 Ueber die Ctenodipterinen des devonischen Systems, 1858, pp. 6-21, with 
plates. 
1 Mag. Nat. Hist. [5] vol. ii. (1878), pp, 1-12, pi. iii. figs. 1-4. 
