UNIO.— Plate XCV. 



pugio is lurge, flat-topped, and viewed from below seems 

 sublamellar. There are a few oblique raised wrinkles on 

 or beyond the ridge. 



Species 517. (Fig. a, b, Mus. Hanley.) 

 Unio crebristkiatxis. Uh. testa crassd,depressiuscttld, 

 valde inaqidlaierali, subrhomboided, ovali vel obovali, 

 coMceiitrice rugosd ; rugis superiie liraformibiis, con- 

 fertis, sapiiis intemiptii, costd mtibonali luteo-fnxcd, 

 laid et planidatd (eliamque ared poslicd dorsaU) 

 costidis ubliquis arcaatis stiperne confertim ornatd, 

 natibus aciilis, prominulu, lunula perparvd, angiislis- 

 shiidque ; margaritd palUde luteo-aurantid ; cardine 

 dente magna trigono .siniplici in utrdque vahiild in- 

 structo ; latiielUs nulUs. 

 The many-striated Unio. Shell thick, rather de- 

 pressed, very inequilateral, subrhonibic, oval, or 

 oboval, with concentric wrinkles which are close-set, 

 raised, and usually interrupted, on the upper part of 

 the disks yellow-brown ; both the broad and flattened 

 umbonal ridge, and the area behind it, adorned above 

 with close-set arched and slanting narrow ridges ; 

 beaks acute and somewhat raised, lunule very small 

 and very narrow, nacre orange-yellow ; hinge solely 

 consisting of a single big simple triangular tooth in 

 each valve. 

 Anthony {Moiwcoiulgleea), Amer. Journ. Conch. 18C5, 



pi. 18. f. 1. 

 Hab. British Birmah (Theobald). 



Although Anthony has not indicated the source of ihc 

 many new species he received from Pegu and the ad- 

 jacent territory, the daring energy of the discoverer of 

 this shell is well known to erpetologists. Conrad has 

 proposed the name Trigonodon as a subgeneric epithet 

 for it. 



Species 518. (Mus. Hanley.) 

 Unio Vondembuschii. Un. testd inaqualiter .subveit- 

 tricosd, crasuusculd, incBquilaterali, subuvald, poslice 

 dilalald, hiferne limid retusd, lavigatd, bruniwd con- 

 colore ; costd umbonali latd, elevatd, postice aiigulald ; 

 ared poslicd latiore, concaviusculd, et rugis elevatis 

 puucis obUquis brevibus inconspiciie instructd ; margine 

 dorsali anlico brevissimo, incurvalo ; natibus proud- 

 mdis, margaritd albidd, seu albo-Uvescente, superne 

 olivaceo-Jlavesceide infucatd ; tubercrdo dentiformi in 

 utrdque valndd; lamelUs nuUis. 



VoNDEMBUScn's Unio. Shell unequally subventricose, 

 thickish, inequilateral, subovate, dilated behind, not 

 retuse below, smooth, of a uniform brown ; umbonal 

 ridge broad, elevated, angulated behind; posterior 

 dorsal area very broad, rather concave, furnished 

 with a few short oblique raised wrinkles; front dorsal 

 edge extremely short and incurved, beaks a little 

 prominent ; nacre whitish or livid white, stained 

 above with yeUowish-olive ; a single tooth-like tuber- 

 cle in each valve ; no lamellre. 



Lea, Trans. Amer. Phil. Soc. ser. 3. vol. viii. (Obs. on 



Unio, vol. iii. p. 60), pi. 18. f. 39. 



Alasmodonta crispata and ZolUngeri, Blousson. 



Hab. Birmah (Theobald) ; Java. 



The raised wrinkles merely run between the ri(ls;e and 

 an obscurely elevated radiating line. 



Species 519. (Mus. Hanley.) 



Unio Peguensis. Un. testd sublenni, subventricosd, ob- 

 longd (nonnunquam abbreviato-oblongd) , satis ineeqid- 

 laterali, luteo-viridescente, concentrici (et antice prts- 

 sertim) confertim rugoso-striatd ; margine ventrali 

 incurvato et atdice acclivi ; ared posticd dorsali latd 

 concaviusculd, rugis elevatis obliquis permultis superne 

 ornatd; umbonibus promimdis ; margaritd pallide 

 rubro-nurantid ; dentibus cardinalibus lamellaribus, 

 corrugalis ; lamelVm lateralibus rectis, longis. 



The Peguan Unio. SheU thinnish, subventricose, ob- 

 liitjg (sometimes shortened), moderately inequilateral, 

 greenish-dull-yellow, with close-set concentric rugose 

 striae (especially in front) ; ventral edge incurved, 

 rising in front; hinder dorsal area broad, rather con- 

 cave, adorned above with very many slanting raised 

 wrinkles ; umboes rather prominent ; nacre pale 

 salmon-coloured ; primary teeth lamellar, wrinkled ; 

 lateral lameUie straight and long. 



Anthony, Amer. Journ. Conch. 1865, p. 351. pi. ^'5. (. 2. 



Ilab. Pegu (Theobald). 



The umboes seem always eroded in the adult, l)ut, 

 judging IVom fragmentary portions, are probably adorned 

 with either grains or broken raised lines. Some indivi- 

 duals are green upon, or beyond, the inconspicuous luu- 

 bonal fold. The left valve, besides its lamellar teeth, has 

 a more or less developed additional one just under the 

 beaks. 



