LAMELLIDEKS. 179 



Var. cylindrica {Uanlaj 6^- Theobald) \ Simpson, AVashington, 

 D.C., Smiths. Inst., Xat. Mus. Proc. xxii, 1900, p. 855. 



TJnio manjinalk var. cylindrica, TI. & T., C. 1. 187G, p. 20, pi. 44, 

 Hg.l. 



As hitherto the name has heeu a mere nomen nudum, and no 

 specimen actually corresponding to Hanley & Theobald's figure 

 being available tlie following short description of the figure itself 

 may be given : — 



Rather more rectangular than tlie typical form, dark olive- 

 green, concentrically banded, especially towards the ventral margin 

 and posterior side, with yellowish brown, and transversely rayed 

 from the urabonal region with dark olive-brown ; interior of shell 

 salmon-coloured. 



Long. 44, lat. 10"2 mm. 



Bcd>. — ? 



Var. hauleyi, Simiyson, Washington, D.C., Smiths. Inst., Xat. 

 Mus. Proc. xxii, 1900, p. 855. 



Unio marginalis var. corriana, II. & T., C. I. 187(3, p. 20, pi. 44, 

 fig. 4. 



Shell more or less indented in the middle, sometimes elongated 

 cylindrical, sometimes compressed and oval-oblong ; cardinal 

 callosity (which is rarely absent) more or less developed ; anterior 

 or hinge teeth almost horizontal, outwardly curved, rather more 

 elongate, or if shorter, rather more prominently elevated. 



Long. 42, lat. 89 mm. (fig. in Con. Ind.). 



Hah. Calcutta, etc. 



Subsp. tliwaitesi {Lea). 



Unio thwaiiesi, Lea, Proc. Acad. Nat. Sci. Philadelphia, iii, 

 1859, p. 152; Joiirn. Acad. Nat. Sci. Philadelphia, iv, 1860, 

 p. 246, pi. 87, fig. 125; Obs. Genus Unio, vii, 1860, p. 64, pi. 37, 

 tig. 125; Reeve, Conch. Icon, xvi, 1865, pi. 2-3, fig. 105; II. & 

 T., C. L 1876, p. 20, pi. 43, tig. 1 ; Pastel, Conch. Sam. iii, 1890, 

 p. 169. 



Marc/arun (Unio) tJiwaitesii, Lea, Syn. 1870, p. 74. 



Unio consobrinus, 11. & T., C. I. 1876, p. 19, pi. 41, fig. 7. 



Lamellidens thioaitcsii (Lea), Simpson, Washington, B.C., Smiths. 

 Inst., Nat. Mus. Proc. xxii, 1900, p. 856. 



Original description : — Testa loDvi, regulariter elliptica, sub- 

 infiata, ina3quilaterali ; valvulis crassiusculis ; natibus prominulis ; 

 epidermide castanea, polita, transverse fasciata ; deutibus cardi- 

 nalibus valde compressis, lamellatis, valde obliquis, in utroque 

 valvulo duplicibus ; lateralibus longis, lamellatis curvisque ; 

 margarita salmonis colore tincta et iridescente. 



JIah. Ceylon {Thwaites). 



If2 



