PETALODOiraD^. 
35 
Teeth having the crown so much reflexed and thickened, that the 
complete dentition forms an exclusively tritoral surface. There are 
three principal rows of teeth, diminishing greatly in size towards 
the front of the mouth ; and one or two smaller rows occur on each 
side, having the summit of the crown less bent and thickened than 
the others. The body is covered with fine, smooth shagreen granules, 
largest apparently on the inferior aspect of the head. 
A.S recognized by K. A. von Zittel’, the inteqmetation of the 
arrangement of the dentition of Janassa proposed by Hancock and 
Howsc ’ is undoubtedly erroneous. 
Janassa bitraminosa (Schlotheim). 
1762. Figure in Dresdinisches Magazin, vol. ii. pt. 4 (//. B. Geinitz). 
1820. TrUobites bitumino$us, E. Schlotheim, Petrefaktenk. p. 30. 
1823. TrUobites bitumirwstis, E. Schlotheim, Nachtrag Petref. pt. ii. 
pp. 30, 87, pi. 22. fig. 0. 
1832. Janassa angulata, O. Miinster, Beitr. Petrefakt. i. p. 67, pi. iv. 
figs. 1, 2. 
1832. Janassa kumboldi, G. Munster, op. cit. i. p. 122, pi. xiv. fig. 4. 
1832. Janassa bituminosa, G. Miinster, <p. cit. i. p. 122. 
1830. Acrodns larva, L. Agassiz, Poiss. Foss. vol. iii. p. 147, pi. 22. 
figs. 23-25. 
1839. Janassa angulata, G. A. Kurtze, Dissert. Petrefakt. Mansfeld, 
p. 20. 
1839. Janassa humboldti, G. A. Kurtze, op. at. p. 20. 
1840. Janassa angulata, G. Munster, op. cit. iii. p. 122, pis. iii. & iv. 
fig. 5 a. 
1840. Bictea striata, G. Miinster, op. cit. iii. p. 124, pis. iii. & iv. figs. 1-4, 
pi. viii. figs. 3, 4, 0-10. 
1840. Janassa angulata, F. Germar, Verstein. Mansfeld Kupferschief. 
p. 26, fig. 15. 
1842. Janassa dictea, G. Miinster, op. cit. v. p. 38, pi. xv. figs. 10-16. 
184.3. Bictea striata =Acrodus larva, L. Agassiz, op. cit. vol. iii. p. 376. 
1843. Byzcnos latipinnatus, G. Miinster, op. cit. vi. p. 50, pi. i. fig. 2. 
1861-6. Janassa angulata, F. Roemer, Bronn’s Leth. geogn. 3rd edit. 
vol. i. p. 717, pi. ix'. fig. 13. 
1851-6. Bictea striata, F. Roemer, tom. cit. p. 718. 
1861. Janassa bituminosa, II. B. Geinitz, Dyas, p. 24, pi. iv. fig. 5, pi. v. 
figs. 1-4. 
1870. Janassa bituminosa, A. Hancock & R. Howse, Ann. & Mag. Nat. 
Hist. [4] vol. V. p. 47, pis. ii., iii. 
1887. Janassa bituminosa, K. A. von Zittel, Handb. Palseont. vol. iii. 
p. 98. 
* Handb. Palseont, vol. iii. (1887), p. 98. 
^ Ann. & Mag. Sat. Hist. [4] toL v. (1870), p. 47. pi. ii. 
