Dr. Ivor Thomas — Devonian Fossils from Cornicall. 101 



I do not know any Upper Devonian AUorisma which suggests 

 close relationship to this species. The nearest resemhlance is afforded 

 by AUorisma muiisteri (d'Arch. & de Vern.) as figured by Professor 

 Beushaiisen f rom the Middle Devonian of Germany (15, p. 255, pi. xxv, 

 figs. 4, 5). Our form differs, however, from this in being considerably 

 smaller, in the valves being less globose, in the more gradual fall 

 from the umbo posteriorly and the less prominence of the umbo 

 above the hinge-line, in the narrower shape of the posterior ligamental 

 area, the straightness of the hinge-line posterior to the umbones, and 

 the presence of the fainter reticulate ornamentation. 



Professor Beushausen's figures differ from those given by d'Archiac 

 and de Yerneuil (1^,, p. 376, pi. xxxvii, figs. 3, 3a) in the sharper fall 

 of the shell anteriorly to the umbones, as well as in the less elongated 

 shape. 



After examination of a poor specimen from Breiniger Berg, 

 doubtfully referred to AUorisma miinsteri, Beushausen suggests the 

 possibility of this form ranging into the Upper Devonian (li, p. 256). 



LIST OF WOEKS CITED. 



1«.Archiac, a. d'. and Verneuil, E. de. — "On the Fossils of the Older 



Deposits in the Ehenish Provinces " : Trans. Geol. Soc. London, 1842, 



ser. II, vol. vi. 

 li. Beushauskn, L. — ^ " Die Lamellibranchiaten des rheinischen Devon mit 



Ausschluss der Aviculiden " : Abhdl. geol. Karte Preussen, 1895, n.f., xvii. 

 \c. Drevekmann, F. — " Fauna der oberdevonischen Tufibreccie von liiingenaubach 



bei Haiger" : Jahrb. d. K. preiiss. geol. Landesanst., 1900, Bd. xxi. 



2. Emmrich, H. F. — " Ueber die Trilobiten": Leonhard und Bronn, Neues 



Jahrb. f. Geologie und Petrefactenkunde, 1845. 



3. Fox, Howard. — "Further Notes on the Devonian Rocks and Fossils in the 



Parish of St. Miuver " : Trans. Roy. Geol. Soc. Cornwall, 1905, 

 vol. xiii, pt. i. 



4. " On the Distribution of Fossils on the North Coast of Cornwall south of 



the Camel " : ibid., 1901, vol. xii, pt. vii. 



5. " On some Fossils from the Coast Sections in the Parishes of Padstow and 



St. Merryn": ibid., 1894. 



6. Fkech, F. — Lethoea Paheozoica, 1S97, Bd. ii, Theil i. 



7. Die Karnischen Alpen, 1894. 



la. " Uber devonische Aramoneen " : Beitr. z. Pal. und Geol. Ostreich- 



Ungarns, etc., 1902, Bd. xiv. 



8. GiJMBEL, C. W. — Geognostische Beschreibuug des Fichtelgebirges, etc., 1879. 



9. GiJRicH, G.— "Das polnische Mittelgebirge " : Yerhaudl. d. Russ.-Kaiserl. 



Miu. Gesellsch. zu St. Petersburg, 1896, Bd. xxxii. 



10. Kayser, E.—Lehrbuch der Geologie, 1908, Theil ii. 



11. " Ueber die Fauna des Nierenkalks vom Eukeberge, etc." : Zeitschr. d. d. 



geol. Gesellsch., 1873, Bd. xxv. 



12. M'CoY, F.— " On the Classification of some British Fossil Crustacea, etc." : 



Ann. Mag. Nat. Hist., 1849, ser. ii, vol. iv. 



13. MiJNSTER, Georg vox. — Beitrage zur Petrefactenkunde, 1842, v. 



14. Phillips, J.— Palfeozoic Fossils of Cornwall, Devon, and West Somerset, 1841. 



15. Reed, F. R. C.—" Classification of the Phacopidie " : Geol. Mag., 1905, 



Dec. V, Vol. II. 



16. Salter, J. W.— British Trilobites (Palreoutogr. Society), 1864. 



16a. Tschernyschew, Th.— " Die Fauna des mittlereu und oberen Devon am 

 Westabhangdes Urals" : Mem. du Com. geol. St. Petersburg, 1887,iii,No. 3. 



17. Wedekind, R.— " Die Cephalopodenfauna des hoheren Oberdevon am 



Enkeberge": Neues Jahrb. f. Min., etc., 1908, Beil.-Bd. xxvi. 



18. Woodward, H.—" Trilobites from the Devonian of St. Minver, Cornwall": 



Geol. Mag., 1905, Dec. V, Vol. II. 



