NODULARIA.. 139 



Marf/aron (TLiio) occatus, Lea, Syn. 1870, p. ol. 

 Unio macilpyititx, Benson, A. M.'X. II. x, 1862, p. 187 ; II. & T., 



C. I. p. 5, pi. 10. ii<,^ 2. & p. (!2, pi. 154, tig. 5. 

 Unio ruffosm, H. & T., C. I. p. 62, pi. 154, tig. 3. 



Orif/inal descriiif ion -.—Testa, plicata, elli[)tiea, rugoso-occafa, 

 coinpressa, vakle iiitcquilaterali, postice biangulatu, autice regu- 

 lariter rotundata ; natibus proiniiuilis, valde compressis, ad apices 

 plicis, pulchris divaricatis ; epidennide luleo-oliva et valde rugosa; 

 deutibus cardiDalibus parvis, compressis, obliquis ; lateralibus 

 sublongis subcurvisque ; margarita alba et valde iridescente. 



f{ab. 33engal ( IF. A, Haines). 



The dimeusious given below are those o£ a specimen in the 

 British Museum with locality " Bengal," which, although some- 

 what larger than that figured 'by Lea, agrees well with his figure 

 and description. 



Long, 22, lat. 42, diam. 15"25 mm. 



It may here be noted that, upon examination, the specimen 

 now in the British Museum, figured by Hanley in the ' Concho- 

 logia ludica ', pi. 10, fig. 4, and \\hich was most probably copied 

 by Sowerby in the ' Conchologia Iconica ' on pi. 79, fig. 412, 

 proves to be a very immature example of a totally different 

 species. 



270. Nodularia (Nodularia) pacliysoma (Benson). 



JSodularia {Nodularia) pachysoma (lienson); Simp.sou, Washington, 

 D.C., Smiths. Inst., Nat. Mus. Proc. xxii, 1900. p. 813. 



Unio pachysoma, Benson, A.M.N. H. x, 1862. p. 18G ; II. & T., 

 C.L 1876, p. 6, pi. 12, tig. 1. 



Maryaron (Unio) pachysoma, Lea, Syn. 1870, p. 03. 



Unio pachystoma, Ptetel, Conch. Sam. iii, 1890, p. 162. 



Orif/inal description : — ^Testa transverse ovato-elongata, ina?qui- 

 lateraii, tenuiuscula, valde tumida, antice brevi rotundata, postice 

 breviter alata, demum raodice acuminata, margine ventrali 

 subrecto, postice ascendente ; disco keviusculo, polito, transverse 

 striatulo, {)Ostice dense striato ; epidermide viridi, fasciis nonnullis 

 luteis radiisque obscuris ornata, postice caerulescenti-viridi ; um- 

 bonibus prominentibus versus apices coutiguos minute radiato- 

 costatis, carina umbonali prominente obtusa, linea secunda 

 radiata interjacente ; dentibus cardinalibus duplicibus, laminatis, 

 lateralibus niodice elongatis, valva? sinistrje solum duplicibus : 

 margarita pallide purpurea, interdum salmonis colore tincta. 



Long. 23, lat. 44, diam. 22 mm. 



Bah. Brahmapootra Hiver, Assam ; also Sawaddy, Burma 

 (Indian Museum Coll.). 



The anterior cicatrices are distinct, the posterior confluent, the 

 dorsal ones under the cardinal teeth. The inner hunhia of the 

 latter in the left valve is sometimes obsolete. 



It differs from U. onndens in being more inflated and devoid of 

 radiate corrugations on the slopes, the posterior side is excavated 



