132 AMERICAN JOURNAL 



Type. 3Iagas pumila, Sby,, fig. 15 a, b. 



3Iagas pumila, Sby., Min. Conch, ii, p. 40, pi, 119, fig. 1 to 5, 

 1818. Bouchard and Pav., Bull. Soc. Geol. de France 

 2nd. ser. v, p. 139, pi. ii, fig. 1 to 11. Dav., An. Nat. 

 Hist. V, pi. XV, fig. 2. Quenst., Handb. p. 476, pi. 

 xxxviii, fig. 15. 



diagas truneata, Rose, in "Woodw'. Geol. Norfolk, pi. 6, fig. 9. 



:«:r.;31, I Woodw., Synopt. Tab. p. 22. fide G,.,. 



Terehratula concava, Lam. An. s. Vert, vi, p. 251, No. 26, 



(1819). Dav., An. Nat. Hist, v, 1850, June. Deshayes, 



Lam. Ed. 2d, vii, No. 26. 



Terehratula magas, Blainv., Man. Mai. p. 512, pi. 54, fig. 1 



(1825). 

 Terehratula pumila, v. Bueh., Mem. Soc. Geol. de France, 



iii, 1st series, p. 216, pi. 19, fig. 5. 

 3Iagas pumila, Gray, B. M. Cat. p. 99, fig. 9, 10. Woodw., 

 Rec. and Foss. sh. p. 217, fig. 117. Chenu, Man. de 

 Conchyl. ii, p. 207, fig. 1059, 1060. King, Permian 

 Foss. p. 8L 

 Hah. Fossil in the cretaceous beds of Europe. 

 In this, the type of the genus, the hffimal valve is almost fiat 

 and the neural valve inflated and nearly touched by the apex of 

 the septum. The beak of the neural valve is strongly recurved, 

 with a minute foramen and rudimentary dcltidium. The car- 

 dinal process is prominent and the area of the neural valve is 

 well defined. Although only found in a fossil state, many of 

 the specimens retain radiating colored bands. 



Magas Davidsoni, De Kon. 



Rhyncliora Davidsoni, De Koninck, fide Dav. An. Nat. Hist. 

 1855, p. 434, pi. x, fig. 4, 4a. 



ITah. Fossil in the cretaceous beds of Mrestricht. 



This species is said by Mr. Davidson to be similar to one of 

 Dalman's types (R. spathidata) and the examination of the in- 

 ternal structure by M. Bosquet, during his work on the creta- 

 ceous Brachiopoda of Maestricht, shows that it is a typical 

 Magas. The apophyses exactly resemble those of 31. pumila, 

 while the hinge margin is much broader than in that species, 

 and nearly straight. The other type of Rhyncliora was Wald- 

 heiniiaf pectinata, Linn., according to Woodward and Dr. Gray. 

 This disposes of a genus badly characterized and founded on an 

 error, which has been the cause of much difficulty and confusion. 

 (See Woodw. Man. Rec. and Foss. Shells, p. 217, note). 



