16 
ACANTHODII. 
P. 3264. Two imperfect mandibular rami with ceratohyals, a jaw- 
fragment, and a detached ceratohyal ; Newsham. 
Enniskillen Coll. 
The following pectoral fin-spines may pertain either to Acantho- 
dopsis or to a large form of Acanthodes :— 
P. 1328. Imperfect spine, slightly arched, with a single longitudinal 
furrow near the anterior margin, preserved for a length 
of 0*11 ; also two associated portions of similar spines ; 
Coal-Measures, Lowmoor, Yorkshire. Eger ton Coll. 
P. 3252. Two imperfect specimens, one larger, one smaller ; Low- 
moor. Enniskillen Coll. 
P. 2285. Fragment of large spine ; Coal-Measures, Carluke, Lanark¬ 
shire. Presented by George Griffiths, Esq., 1882. 
Genus CHEIRACANTHUS, Agassiz. 
. . _ [Poiss. Foss. vol. ii. pt. i. 1835, p. 125.] 
/'rzx. fusiform, laterally compressed. Teeth minute or absent; 
/VV ; ^ ' orbit with ring of four circumorbital dermal plates. Pectoral 
fins large ; pelvic pair well developed. A single dorsal fin, arisin 
opposite the space between the pelvic fins and the anal. 
O* 
© 
Gheiracanthus murchisoni^ Agassiz. 
1835. Gheiracanthus murchisoni, L. Agassiz, Poiss. Foss. vol. ii. pt. i. 
p. 126, pi. i c. figs. 3 ; 4. 
1835. Clieiracanthus minor , L. Agassiz, ibid, pt i. p. 127, pi. i c. fio-. 5. 
1844. Gheiracanthus microlepidotus, L. Agassis, Poiss. Foss. V. G. R. 
p. 38, pi. xv. figs. 1-3. [British Museum and Museum.] ItfP.lV.. 
1848. Chiracanthus lateralis, F. M‘Coy, Ann. Mag. Nat, Hist. [2] 
vol. ii. p. 300. [Woodwerdian Museum, Cambridge.] 
1848. Chiracanthus pulverulentus, F. M‘Coy, ibid. p. 299. [Ibid.] 
1855. Chiracanthus lateralis, F. M‘Coy, Brit. Palmoz. Foss. p. 582. 
1855. Chiracanthus microlepidotus, F. M‘Coy, ibid. p. 583. 
1855. Chiracanthus minor, F. M‘Coy, ibid. p. 583. 
1855. Chiracanthus murchisoni, F. M‘Coy, ibid. p. 583. 
1855. Chiracanthus pulverulentus, F. M‘Coy, ibid. p. 583, pi. ii b. fio-. 2. 
1888. Gheiracanthus murchisoni, R. H. Traquair, Geol. Mag. [3] vol. v. 
P-612. /ns£. <q>o/. Un/v- N&ucWat&l, 
Type. Imperfect fish ; unknown ■ (ohm Murchison Collection). 
The type species, usually attaining a length of about 0-16-0-2, 
but occasionally measuring as much as 0-3. Body elongated and 
slender, the greatest depth being nearly equal to the length of the 
