186 Annals of the South African Museum. 



AMBOCCELIA UMBONATA (Conrad). 

 (Plate XXIII., fig. 5.) 



1842. Or this umbonata, Conrad, Journ. Acad. Nat. Sci. Philadelphia, 



viii., p. 264, pi. xiv., fig. 4. 



1843. Orthis nucleus, Hall, Geol. New York; Eep. Fourth District, 



p. 180, fig. 8. 

 1846. OrtMs umbonata, Eouault, Bull. Soc. Geol. Fr., ser. 2, iv., 



p. 322, pi. iii., fig. 8. 

 1857. Orthis iimbojiata, Hall, Tenth Eep. N.Y. State Cab. Nat. 



Hist., p. 167, figs. 1-3. 

 1860. Amboccelia umbonata, Hall, Thirteenth Eep. N.Y. State Cab. 



Nat. Hist., p. 71. 

 1867. Amboccelia 2imbonata, Hall, Palgeont. New York, vol. iv., 



p. 259, pi. xliv., figs. 7-8. 

 1887. Amboccelia umbonata, Oehlert, Bull. Soc. Et. Scient. Angers, 



p. 6, pi. v., figs. 11-16. 

 1889. Amboccelia umbonata, Nettelroth, Kentucky Fossil Shells, 



Mem. Kentucky Geol. Surv., p. 86, pi. xvii., figs. 



25, 26. 

 1893. Amboccelia umboimta. Hall and Clarke, Palaeont. N.Y., vol. 



viii., pt. ii., pi. xxix., fig. 17 ; pi. xxxix., figs. 4-9. 

 1895. Martinia umbonata, Herrick, Geol. Ohio, vii., pi. xx., 



fig. 3. 

 1897. Amboccelia umbonata, Schuchert, Syn. Amer. Foss. Brach. 



(Bull. U.S. Geol. Surv., No. 87), p. 141. 



This well-marked species is represented in the collection by two 

 pedicle valves, one of which (No. 130) is an internal cast showing 

 the beak, muscular impressions, and hinge apparatus. The charac- 

 teristic features of the exterior are also well preserved, and I have 

 compared them with typical examples of A. umbonata from the 

 Hamilton Group of North America without detecting any points of 

 difference. Though this species has not been recorded previously 

 from South Africa, it has been found in Western France by Eouault 

 and Oehlert. 



Dimensions. — Length 10 mm. 



Localities.— C^o. 130) Slang Fontein, Ceres. (No. 137) Gydo Pass, 

 Ceres. ? (No. 211) Uitkomst, Ceres, 



