474 PROCEEDINGS OF THE ACADEMY OF 



margin of the anterior area if continued ; the superior margin is rough and 

 bony, forming a broad area defined by a sharp crested ridge, and emarginated 

 at the junction of the wing. Hinge tubercles large, with a hook-shaped pro- 

 cess from each, by which the valves are interlocked ; the wing is formed by a 

 sharp shell-like ridge, and is smooth and slightly excavated. The cavity of 

 the beak is filled with a spongy calcareous matter, from which issues the del- 

 icate and flattened subumbonal process which presents its flat side to the 

 valve, and at about one-third its length forms a decided elbow backwards. 



Length from before backwards inch ; from above downwards a little less. 



Pallettes very large and long, stilt-shaped ; the style long and subulate, 

 slightly flexuous, bony, surrounded by a broad dilatation or step, concave on 

 one side and convex on the other ; its upper surface deeply excavated, on this 

 is placed the blade, which is three-fourths as long as the style, thin, linear, 

 obliquely truncated at tips, about one-third the width of the step. 



Length of style 7-10ths ; of blade 4-10ths inch. 



Brought by Rev. F. Mason and Rev. J. Benjamin from Tavoy. 



In size and solidity this exceeds all the species yet described, it is chiefly 

 distinguished by the great size of the anterior triangular portion when com- 

 pared with the posterior alar portion or auricle. 



The form of the pallettes also is entirely different from any yet described ; 

 nor do I find any mention elsewhere of the spongy calcareous growth in the 

 umbonal cavity." Gould. 



Genus UPEROTIS, Guettard. 



Uperotis, Guettard, Memoirs, ii. p. 128. Adams, Genera, ii. p. 333. 



Guetera, Gray, Syn. Brit. Mus., 1842. Gray, Zooh Proc, p. 188, 1847. Gray, 



Ann. and Mag. Nat. Hist., 2d ser., viii. p. 381. 

 ' Serpula, (part.) Mawe, Conch., p. 194. 

 Fistulana, (part.) Blainville, Diet. Sc. Nat., xvii. p. 82. Bosc. Hist. Coq., ii, 



p. 203. Griffith, Cuvier Regne Anim., xii. p. 124. Guerin, Iconog. 



Reg. Anim. Moll., t. 33. Hanley, Desc. Cat., p. 3. Lamarck, Anim. 



sans. Vert., v. p. 432; id. 2d edit., vi. p. 25. Potiez et Miuhaud, Gal- 



lerie des Moll., ii. p. 272. Schroter, Einleit, ii. Walch, Naturf., x, 



p. 38. 

 Teredo, (part.) Catlow, Conch. Nomenc, p. 2. Cuvier, Regne Anim., edit. 



Audouin Moll., p. 252. Deshayes, Traite Elem., pt. ii. p. 47. De- 



shayes, Note in 2d edit., Lamarck, Anim. sans. Vert., vi. p. 39. Dill- 



wyn, Desc. Cat., p. 1087. Gray, Phil. Mag., 1827, p. 409. Jay, Cat., 



4th edit., p. 9. Wood, Index Test., t. 38. 

 Dr. Gray includes in his genus Guetera, besides the U. c 1 a v a, two other 

 specimens, which he names : 



G. lagenuala? this = Cucurbitula cymbia, Spengler (GASTROCHiE- 



NID.E). 

 G. corniformis, this = tube of Teredo Norvagica, Spengler. 



U. clava, Gmelin, sp. 



Teredo clava, Gmelin, Syst. Nat., p. 3748. Dillwyn, Desc. Cat., p. 1090. 



Gray, Phil. Mag., 1827, p. 410. Guettard, Mem., iii. t. 7, f. 69. 



Wood, Index Test,, t. 38, f. 4. 

 Guetera clava, Gray, Ann. Mag. Nat. Hist,, 2d ser., viii. p. 386. 

 U. clava, Adams, Genera, ii. p. 333. 

 Fistulana gregata, Lamarck, Anim. sans. Vert., v. p. 435 ; ditto, 2d edit., vi. 



p. 31. Bosc, Hist. Coq., ii. p. 204. Encyc. Meth., t. 167, f. 614. 



Griffith, Cuv. Reg. Anim., xii. t. 8, f. 3. Guerin, Iconog. Reg. Anim. 



Moll., t. 33, f. 3. Hanley, Desc. Cat., p. 3. Potiez et Michaud, Gal- 



lerie des Moll., ii. p. 272. Schroter, Einleit., ii. p. 574, t. 6, f. 20. 



Walch, Naturforsch., x. p. 38, t. 1, f. 9, 10. 



[Sept. 



