MAZATL1.N UNIVALVES 427 



GENUS CHEMNITZIA, D'Orl. 



Nat. Hist. Canar. 1839. Forbes fy Hani. Br. Moll. vol. iii. 



p. . Woodw. Man. Moll. p. 126. 

 TurboniUa, Risso, Nat. Hist. Eur. Mer. vol. iv. p. 224, 1826. 



Phil. Handb. Conch, p. 193. H. fy A. Ad. Gen. vol. i. p. 230. 

 Parthenia, Lowe, Ann. Mag. Nat. Hist. vol. vi. p. 511, 1841. 

 Pyrgiscus, Phil. Arch.f. Nat. vol. i. p. 50, 1841. 

 Prramis + Jaminea, Brown, Brit. Conch. 

 Amoura, Mull. 

 Orthostelis, Arad. fy Magg. Cat, Reg. p. 189, ? 1844. 



SPECIES TTPIC^E. Anfractibus planatis. 



SECTION A. Without spiral sculpture, 

 (a.) Ribs interrupted at the periphery. 



518. CHEMNITZIA ? PANAMENSIS, C. B. Ad. 



Pan. Shells, no. 227, pp. 168, 312. 



Tablet 1989 contains a dead specimen which appears suf- 

 ficiently like the type in Mr. Cummg's Collection. It has 5 

 whirls, the apex being deficient both in this and in the type. 

 The species is rather broad, with very flat whirls, stout, rather 

 slanting ribs, and very deeply cut grooves as far as the peri- 

 phery. It measures long. '075, lot. '025. 

 Hob. Panama ; 11 sp. in the sand on the reef, between high 



water and half tide levels ; C. B. Adams. PMazatlan ; 1 sp. 



off Chama ; ISpool Col. 



519. CHEMNITZIA C-B-ADAMsn, n. s. 



Ch. t. gracili, alba, elongatd ; vertice nucleoso anfr. iii. 

 prominent ibus, declivi, marginibus spires rectis superante ; 

 anfr. ii. prope apicem rotundatis ; deinde vii. planatis, suturd 

 impressd ; liris circiter xviii. rectis, solidis, obtusis, ad peri- 

 pheriam subito obsolelis ; basi subrotundatd ; labro tenui ; 

 columelld tenui, vix intortd. 



Shell intermediate between Ch. aculeus and Ch. Panamensis, 

 with all the whirls except those next the apex flattened. The 

 apex is very large, with 3 tumid whirls, set rather slanting on 

 the axis. It is named in remembrance of Prof. Adams of 

 Amherst, U. S. whose early death has deprived science of one 



