BYT. — CHI.] 



PISCES. 



589 



Asterolepis, but distinguished by the 

 course of the furrows and shape of 

 the plates ; it has longer articulating 

 plates in the limb or arm, and has been 

 otherwise distinguished, though closely 

 related to both genera. Type B. or- 

 natus. 

 canadensis, Whiteaves, 1880, (Pterichthys 

 canadensis,) Am. Jour. Sci. and Arts, 

 3d. ser., vol. 20, p. 135, Up. Devo- 

 nian. 

 Bythiacanthus, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 444. [Ely. 

 bythios, deep ; akantha, spine.] Fin 

 spines deeply imbedded, laterally com- 

 pressed, exposed part recumbent, 

 tuberculated ; posterior face low, keeled ; 

 pulp cavity forming a deep channel in 

 the posterior side of the base. Type B. 

 vanhornii. 

 siderius, Leidy, 1873, (Asteracanthus sid- 

 erius,) Ext. Vert. Fauna, p. 313, St. 

 Louis Gr. 

 vanhornii, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 445, St. 

 Louis Gr. 

 Calopodus, St. John & Worthen, 1875, Geo. 

 Sur. Ill, vol. 6, p. 403. [Ety. kahs, 

 beautiful ; odous, tooth.] 

 Teeth in general form 

 like Petalodus, but dis- 

 tinguished by the tur- 

 gid, subcorneal, unsym- 

 metrical crown. Type C. 

 apicalis. 



apicalis, St. John & Wor- Fig. 1105 — Calo- 

 then, 1875, Geo. Sur. 111., R" dus M a g ic % 

 vol. 6, p. 403, Middle diam. ' 

 Coal Meas. 

 Carcharopsis, Agassiz, 1843, Recherches sur 

 les Poissons Fossiles, vol. 3, p. 313. 

 [Ety. carcharopsis, shark-like.] Prin- 

 cipal cusps very strong, erect, com- 

 pressed in front, rounded behind, 

 broadly expanded at base; lateral an- 

 gles sharp, crenulated ; extremities oc- 

 cupied by isolated, conical, lateral 

 denticles ; coronal faces smooth or 

 faintly striated vertically ; base in out- 

 line like Clado- 

 dus, moder- 

 ately produced 

 and broadly 

 rounded poste- 

 riorly; anterior 

 face sinuous, 

 termin ati ng 

 below in a 

 ridge; inferior 

 surface exca- 

 vated. Type C. 

 prototypus. 

 wortheni, New- 

 berry, 1866, Geo. Sur. 111., vol. 2, p. 69, 

 SubcarbonitVrous. 

 Ckphalaspjs, Agnssiz, 1836, Recherch. Pois. 

 Foss., t. 2, p. 135. [Ety. kephale, head ; 

 aspis, shield.] Entire skeleton external ; 

 head shield very large, subcrescent- 



FiG. 1106.— Carcharopsis 

 wortheni. 



iform when depressed but in better, 

 condition showing an arching over 

 the top of the 

 head, cov- 

 ered with 

 d i s c o i dal, 

 sculptured, 

 bony plates, 

 with ' the 

 crescent 

 horns di- 

 rected back- 

 ward; eyes 

 large, ellip- 

 tical, on each 

 side of the 

 upper cen- 

 tral part oli.,,„ ,,„_ .. , , , , n, 

 .i r . j . bio. 110/ . — i ephalaspis lyelll. 

 tne Iieaa ; Head >hield depressed, and 

 body rapidly showing the jointed angular 

 tapering an- outline of part of the body, 

 gularon top, 



and presenting a jointed appearance 

 somewhat like a trilobite; dorsal, anal, 

 and caudal fin, the latter like a paddle 

 or oar. Type C. lyelli. 



campbeltonensis, Whiteaves, 1881, Can. 

 Nat., vol. 10, Devonian. 



dawsoni, Lankester, 1870, London Geo. 

 Mag., Devonian. 

 Ceratodus, Agassiz, 1833, Recherche? sur 

 les Poissons Fossiles, t. 1, p. 129. '[Ety. 

 keras, horn ; odous, tooth.] Teeth large, 

 thick, longer than wide, very porous ; 

 crown transversely sulcated. Type C. 

 latissimus. 



favosus, Cope, 1884, Pal. Bull., No. 39, p. 

 28, Permian. 



paucicristatus, Cope, 1877, Proc. Am. Phil* 

 Soc, p. 54, Permian. 



vinslovii, Cope, 1876, Proc. Am. Phil. Soc, 

 p. 410, Permian. 

 Chirodus, McCoy, 1848, Ann. and Mag. Nat. 

 Hist., vol. 2, p. 130. [Ety. cJieir, the 

 hand ; odous, tooth.] Tooth fan-shaped, 

 thick, flattened ; anterior broad, margin 

 deeply divided into lobes; inner nearly 

 straight margin has a small, recurved, 

 thumb-like lobe projecting nearly at 

 right angles from the middle of its 

 length, preventing the mesial junction 

 of the tritors of each side of the jaw ; 

 inner marginal lobe the longer; surface 

 minutely punctured. Type C. pesranse. 

 Not definitely known in America. 



acutus, Newberry, 1857, Proc. Acad. Nat. 

 Sci. , vol. 8, p. 99, Coal Meas. Too poorly 

 defined to warrant recognition. 

 Chirolepis, Agassiz, 1833, Recherches sur 

 les Poissons Fossiles, t. 1, p. 128. [Ety. 

 cheir, hand ; lepis, scale.] Bones of the 

 head sculptured ; shoulder-bone and 

 fins osseous ; pectorals large, reaching 

 near the ventral fin, and ventral reach- 

 ing near the anal fin ; dorsal fin small 

 and opposite the posterior part of the 

 anal fin; tail well-developed, principally 

 on the lower side ; scales small, sculp- 



