240 
SIRENOIDEI. 
p. 756. Impression of a large crushed fish, and two portions of 
small individuals ; Caithness. Egerton Coll. 
P. 3374, P. 4597. The caudal half of two small individuals, and a 
mass of scales of a large fish; Caithness. 
Enniskillen Coll. 
P. 3374 a. Incomplete small fish, probably of this species; Orkney. 
Enniskillen Coll . 
19808. Small fish, either of this or the following species ; Caithness. 
Purchased , 1845. 
P. 3373. Imperfect small fish, probably of this species ; Orkney. 
Enniskillen Coll. 
P. 825. Scales, probably of this species ; Edderton, near Tain, Boss- 
shire. Egerton Coll. 
P. 1175. Bemains of head and trunk, probably of this species; 
Edderton. ' Egerton Coll. 
Dipterus macropterus, Traquair. 
1888. Dipterus macropterus , B. H. Traquair, Geol. Mag. [3] vol. v. 
p. 508. 
1889. Dipterus macropterus , B. H. Traquair, ibid. vol. vi. p. 97, pi. ii. 
Type. Nearly complete fish ; Edinburgh Museum. 
A species usually attaining a length of about 0-2. Form and pro¬ 
portions of htad an 1 trunk as in the type species. Anterior dorsal 
fin relatively very small; posterior dorsal very large, much longer 
than high. Scaies relatively thin. 
Form. Sj- Loc. Lower Old Bed Sandstone: Caithness. 
42473-78. Six specimens, four showing the nearly complete fish, 
the others also exhibiting several details of structure ; 
John-o’-Groats. Peach Coll. 
42479. Portion of axial skeleton and scales of a comparatively large 
fish; John-o’-Groats. Peach Coll. 
The following species, being known only by detached dental 
plates, are doubtfully of this genus :— 
Dipterus (?) serratus, Eichwald. 
1844. Ctenodus serratus, E. von Eichwald, Bull. Soc. Imp. Nat. Moscou, 
vol. xvii. p. 828. 
1845. Ctenodus keyserlingii, Agassiz, Poiss, Foss, V, G. B. p. 122, 
pi. xxxiii, figs. 32-35. 
