638 BRITISH PALAZOZOIC FOSSILS. [ Pisces. 
Genus. PHYSONEMUS (4g. name only). 
Gen. Char.—Fin-spine of small or moderate size, much compressed, with a variable backward curvature ; 
base of insertion large; posterior edge with two rows of small denticles. Surface covered with very numerous 
cord-like longitudinal ridges, which swell at short regular intervals into smooth bubble-like tubercles. 
Prysonemus arcuatus (A/°Coy.) Pl. 3. I. fig. 29. 
Desc.—Ray wide, much curved, with a broad, dilated, bilobed base; a specimen imperfect at the tip, four 
and a half inches long, measured along the anterior curve, is regularly arched the fourth of a circle; the 
width at the broken distal end is five lines; the width at point of entry into the flesh eleven lines; length 
of base one inch nine lines; width of base one inch one line; longitudinal rounded ridges yery numerous, 
about twelve to fifteen in the space of half an inch, less than their own diameter apart, dilated into rounded, 
smooth, bubble-like tubercles, which are nearly twice their diameter apart; some of the tubercles occasionally 
flattened and transversely oblong; the narrow sulci between the ridges have usually two or three obscure 
longitudinal strie; on the posterior edge are two irregular alternating rows of obtusely-pointed tubercles 
finely stellated by radiating strize at base, and about one line in diameter. 
Distinguished from the Physonemus subteres (Ag.) by its much greater size, more numerous ridges, and 
wide arcuate form. 
Position and Locality.—V ery rare, from the carboniferous limestone of Armagh. 
Explanation of Figures.—P\. 3. 1. f. 29, large specimen, shewing the perfect base, natural size; fig. 
29 a, portion of surface magnified ; 29d, one of posterior teeth, magnified. 
PHYSONEMUS SUBTERES (Ag. name only). PI. 3. I. fig. 30. 
Our specimen of this species is unfit for description, being a fragment five lines long, straight, without 
perceptible tapering, one and half lines wide, about four ridges in the space of one line; the intervening spaces 
being rather wider than the ridges themselves, which swell at regular alternate intervals into oval, smooth 
tubercles, about their own diameter apart ; intervening spaces with about three longitudinal punctured striz. 
I have seen specimens about twice the above size, and the species is easily distinguished from the 
P. arcuatus by its small dimensions, slender tapering form, and straightness; two small rows of teeth on the 
posterior side. 
Position and Locality.—Rare in the carboniferous limestone of Armagh. 
Explanation of Figures.—P1. 3. 1. fig. 30, fragment natural size; fig. 30 a, portion of surface magnified. 
Genus. PQECILODUS (Ag. name only). 
Gen. Char.—Teeth formed and disposed as in Cochliodus; terminal tooth obliquely trigonal, slightly con- 
voluted; median tooth narrow, much convoluted; all the teeth longitudinally marked with thick, step-like, 
oblique, flattened wrinkles, apparently at right angles to the articular edges; surface porous. 
This should only be viewed as a subgenus of Cochliodus, for the number and form of the teeth, with the 
strong inrollment, particularly of the median tooth over the outer part of the jaws, seems to be the same in 
both; the only tangible difference of the present teeth being the more or less distinct longitudinal ridges, which 
cross the teeth, parallel to the inner margin. 
Paciopus atirormis (M*Coy). 72.3, & Fey: 7 PL og) 
Ref —M°Coy, Ann. Nat. Hist. 2nd Series, Vol. IT. 
Desc.— Wing-shaped, or contorto-subtrigonal, narrow before, broad and subtruncate behind; inner 
straight margin thin, higher in the middle than at each end, the surface seeming concave from thence to the 
external oblique margin, which is abruptly deflected, much thickened ; rounded, strongly arched downwards at 
