600 



PISCES. 



[HOM. LIO. 



Homicanihus, Agassiz, 1845, Pois. Foss. [Ety. 

 homos, similar ; akantha, spine.] 



gibbosus, see Amacanthus gibbosus. 



gracilis, Whiteavea, 1889, Trans. Roy Soc., 

 Can., vol. 6, p. 77, Low. Devonian. 



rectus, see Marracanthus rectus. 

 HYBOCLADODUS, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 284. [Ety. hybos, 

 hump; Cladodus, a genus.] Teeth 

 small, strongly cuspidate, base resem- 

 bling that of a Cladodus, being elliptical 

 and broadly expanded, with a more or 

 less prominent antero-posteriorly com- 

 pressed median cone, both surfaces of 

 which are plicated and resemble the 

 crown of a Hybodus; anterior face 

 nearly straight, curved laterally, termi- 

 nating below in a well defined marginal 

 border or ridge, posterior margin broadly 

 rounded, inferior surface excavated im- 

 mediately behind the marginal border, 

 with a beveled space extending along 

 the posterior margin, superior face more 

 or less convex and beveled to the pos- 

 terior edge ; both coronal surfaces verti- 

 cally marked with plicfe. Type H. 

 plicatilis. 



compressus, Newberry & Worthen, 1866, 

 (Helodus compressus,) Geo. Sur. 111., 

 vol. 2, p. 78, Burlington Gr. 



intermedius, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 287, Keokuk Gr. 

 nitidus, St. John & Wor- 

 then, 1875, Geo. Sur. 

 111., vol. 6, p. 288, Kas- 

 kaskia Gr. 



plicatilis, St. John <fc Wor- 

 then, 1875, Geo. Sur. 

 III., vol. 6, p. 286, Burlington Gr. 



tenuicostatus, St. John & Worthen, 1875. 

 Geo. Sur. 111., vol. 6, p. 286, Keo- 

 kuk Gr. 



JANASSA, Munster, 1839, Beitrage Petrefak- 

 tenkunde, vol. 1, and Agassiz in Poiss. 

 Foss., t. 3, p. 375. [Ety. mythological 

 name.] Teeth have a tabulated struc- 

 ture and enameled, wavy crown ; small 

 in front and larger toward the posterior 

 part of the jaw; jaw-bone rough and 

 tranular. Type J. angulata. 



gmlfiana, Cope, 1877, (Strigillina gurlei- 

 ana,) Proc. Am. Phil. Soc., p. 191, 

 Permian. 



linimiformis, Cope, 1877, (Strigillina lin- 

 jjuiformis,) Proc. Am. Phil. Soc., p. 53, 

 Permian. 



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

 Sur. 111., vol. 6, p. 280. [Ety. Lambda, 

 a Greek letter; odous, tooth.] Teeth 

 email, base posteriorly produced and 

 laterally expanded, broadest behind the 

 cornua ; a single strong, slightly sig- 

 moidally curved, recurved, eccentric 

 cornua arises from the anterior angle 

 of the base, terminates in a sharp apex, 

 compressed in front, broadly rounded 

 behind, with more or less distinct cut- 

 ting edges and vertical costse. It is 

 distinguished from Cladodus by the 



Fro. 1139.-Hybo- 

 cladodas plica- 

 tilis. 



FIG. 1140. Lamb- 



single coronal cornua, and the absence 

 of lateral denticles ; the basal portion 

 bears some resemblance to Thrinacodua. 

 Type L. cost at us. 



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

 Sur. 111., vol. 6, p. 281, Burlington Gr. 



calceolus var. robustus, St. John & Wor- 

 then, 1866, Geo. Sur. 111., vol. 6, p. 282, 

 Keokuk Gr. 



costatus, St. John & Wor- 

 then, 1875, Geo. Sur. 111., 

 vol. 6, p. 280, Burling- 

 ton Gr. 



hamulus, St. John & Wor- ^doduVcostatus" 

 then, 1875, Geo. Sur. 

 111., vol. 6, p. 283, Kaskaskia Gr. 



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

 Sur. 111., vol. 6, p. 284, Kaskaskia Gr. 



transversus, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 282. St. Louis Gr. 

 LECRACANTHCS, St. John & Worthen, 1875, 

 Geo. Sur. 111., vol. 6, p. 475. [Ety. 

 lekroi, the antlers of a stag; akantha, 

 spine.] Spines long, tapering, curved, 

 laterally compressed, stellate tubercles 

 irregularly disposed; base thin, ex- 

 panded ; pulp cavity large ; apex trans- 

 versely expanded and armed with strong 

 denticles. Type L. unguiculus. 



unguiculus, St. John & Worthen. 1875, 

 Geo. Sur. 111., vol. 6, p. 476, St. 

 Louis Gr. 



Leptacanthus, Agassiz. 1837, Poiss. Foss., vol. 

 3. [Ety. leptos, slender ; akantha., spine.] 



occidentals, see Acondylacanthus occiden- 



talis. 



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

 Sur. 111., vol. 6, p. 335. [Ety. leios, 

 smooth ; odous, tooth.] Teeth resem- 

 bling Orodus; crown arched, laterally 

 and vertically ; basal margins con- 

 structed and sharply defined from the 

 base ; apex with obscurely defined 

 lateral crests; convex in either face; 

 anterior face produced beneath the 

 median cone, and both faces occupied 

 with faint vertical eulci, producing ob- 

 scure secondary prominences ; surface 

 smooth, punctate, or verrucose ; base as 

 in Orodus, rejatively deep. Type L. 

 calcaratus. 



calcaratus, St. John 

 & Worthen, 1875, 

 Geo. Sur. 111., vol. 

 6, p. 336, Bur- 

 lington Gr. 

 calcaratus var. gros- 

 sipunctatus, St. 

 John & Worthen, 

 1875, Geo. Sur. 111., vol. 6, p. 337, Keo- 

 kuk Gr. 



LIOGNATHUS, Newberry, 1873, Ohio Pal., 

 vol. 1, p. 306. [Ety. lis, smooth ; gnithos, 

 the jaw.] Jaw the only part yet 

 known ; spatulate, dentate only at and 

 near the anterior extremity ; resembles 

 Coccosteus. Type L. spatulatus. 



spatulatus, Newberry, 1873, Ohio Pal., vol. 

 1, p. 306, Up. Held. Gr. 



FIG. 1141. Lloduscalca 

 rat us. 



