586 



PISCES. 



[ACA. ACO. 



FAMILY ICHTHYODORULITES. Acondylacanthus, Amacanthus, Anaclitacan- 

 thus, Asteroptychius, Batacanthus, Bythiacanthus, Compsacanthus, Ctena- 

 canthus, Cyrtacauthus, Drepauacanthus, Edestus, Erismacanthus, Eune- 

 macanthus, Ganipsacanthus, Gisacanthus, Glyramatacanthus, Gyracanthus, 

 Horaacanthus, Lecracanthus, Listracanthus, Machseracanthus, Marracan- 

 thus, Oracanthus, Orthacanthus, Physonemus, Piiigeacanthua, Stenacan- 

 thus, Xystracanthus. 



ORDER RAIINA. 

 FAMILY PSAMMODONTID^E. Copodus, Psammodus. 



ACANTHAPPIS, Newberry, 1875, Ohio Pal., 

 [Ety. akantha, spine ; 

 Cranium plates some- 



, , 



vol. 2, p. 36. [Ely. akantha, spine; 

 aspis, shield.] Craniu 



what quadrangular at 

 one end, then abruptly 

 bending to one si<le, 

 and prolonged to an 

 acute point; surface 

 carinated and tuber- 

 culated. Type A. ar- 

 mata. 



armata, Newberry, 1875, 

 Ohio Pal., vol. 2, p. 37. 

 Up. Held. Gr. 

 ACANTJIODES, Aga&siz, 1833, 

 Recherches sur les 

 Poiss. Fus*., vol. 1, p. 

 19. [Ety. akantha, 

 spine.] Fish lepidoid, 

 mouth wide ; lower 

 jaw longer than the 

 upper; teeth brush- 

 like ; scales small ; dor- 



sal fin 



opposite 



anal; 



pectoral Fi- 1097. Acantliaspis armata. 



In rtrp- PI'tte bearing spine from left 



i a. i g c , side of crau i um 



first ray 



of each fin strong, large, 

 stiff; rays of caudal fin 

 close. Type A. bronni. 

 affinia, Whiteaves, 18S9, 

 Tians. Roy. Soc. Can., 

 vol. 6, p. 77, Low. Devo- 

 nian. 



concinnus, Whiteaves, 

 18.S9, Trans. Roy. Soc. 

 tulosus. He- Can., vol. 6, p. 77, Low. 

 duced outlines Devonian, 

 probably ^In' AcANTnoLEPis, Ne w b e r r y , 

 their relative 1875, Ohio Pal., vol. 2. 

 positions. p_ 38 [Ety. akantha, 



spine ; lepis, scale.] Tuberculated cran- 

 ial or dermal plates, having a prevailing 



Fio.1098. Acan- 

 tliolepls pus- 

 II e- 



spatulate outline; some are thin and 

 have the appearance of large, elon- 

 gated, unsymmttjical scales; others are 

 stronger and produced into points that 

 sometimes become spines. Type A. 

 pustulosa. 



pustulosa, Newberry, 1875, Ohio Pal., 

 vol. 2, p. 38, Up. Held. Gr. 

 ACONDYLACANTHUS, St. John & 

 Worthen, 1875, Geo. Sur. 

 III., vol. 6, p. 432. [Ety. 

 akondylos, without bony 

 knobs; akantha, spine.] Fin 

 rays long, gradually taper- 

 ing, laterally compressed, 

 moderately curved posteri- 

 orly ; lateral faces longitudi- 

 nally fluted; coatae smooth, 

 enameled, increasing by bi- 

 furcation and implantation ; 

 posterior face excavated 

 longitudinally, without me- 

 dian keel ; postero-lateral 

 angles bear- 

 ing a row of 

 d o w nward 

 hooked den- 

 ticles; pulp 

 cavity occu- 

 pying the 

 posterior half 

 of the spine. 

 Type A. gra- 

 cilis. 



seq uicoatatus, 

 St. John & 

 W o r t h e n , 

 1875, Geo. 

 Sur. III., vol. 6, p. 434, 

 Keokuk Gr. 



gracilis, St. John & Wor- 

 then, 1875, Geo. Sur. 

 III., vol. 6, p. 433, Wa- 

 verly or Kinderhook Gr. 

 mudgianus, St. John & 

 Worthen, 1883,Geo. Sur. 



^'- 1 ea 7 'P- 244 ' U P-r I0 .1099.-Acon- 

 V./OHI lueas. elylitca u tl) us 



nuperus, St. John & Wor- grucilis. Side 

 then, 1883,- Geo. Sur. view of spine 

 111., vol. 7, p. 242, Up. ?' A dfam ' 

 Coal Meas. 



occidentalis, Newberry & Worthen, 

 1866, (Leptacanthus occidentalis,) 



