M Y C E T P U S 



Gfiius MYCETOPUS. 



Ti'slii biralvis, bimusculosa, amjusthsiiua, laternlih'r cluii- 

 'jrila, Imvigata, epichrmidf. fascit aut oUvaceil iinhila, 

 ulriiique liiam, postiw latior, iidiiit margaritacm, 

 iiuirgine cardij/rdi temd, I'ecfu, edeidido. 



Shell bivalve, bimuscular, very narrow, laterally elonjiated, 

 sniootli, covered with a brown or olive epidermis, 

 gapiiii? at both ends, wider posteriorly, pearly with- 

 in, eardiual margin thin, straight, witliout teetii. 



The most remarkable character of this genus of fresli- 

 water bivalves is in the foot of the animal, which is very 

 long, and terminates in a sort of button. The shells 

 might be described as very narrow, soleniform Anodons ; 

 n(n- is it by any means certain that all the species here 

 enunjcrated really are members of the genus. In one or 

 two cases, the animals being unknown, the shells are as- 

 sociated with it on account of their resemblance in form. 

 Tiie rivers of South America appear to be the dwell ing- 

 jjlaces of the Mycetopodes, with the exception of M. rit- 

 ijosiis, I'roin Victoria, and M. euiarr/liKdiis, from Siam. 



(lie, pale 



Species •2. (JIus. Cuming in Urit.) 

 {J, id Fig. 3, a, PI. HI.) 

 Mycetopus siliquosus. Mgr. imld lavigald, .suhcn- 

 tiealn,obh)iign. rnlde iiiicquiltili'raH.compres.'id ; latere 

 iiidico hrcri, liimde, teriidno rolnndo : hdcm postico 

 producing hdiKsciilu, oldiise mguluto, vmrgine lenmindi 

 ohliijiii tniiicrdn, viarghie veidraJi convexinscido. 

 TnE POD Mycetopus. Shell smooth, subcuneate, ob- 

 long, very inequilateral, compressed ; anterior side 

 short, gaping, round at the end ; posterior side pro- 

 duced, rather wider, obtusely angular, terminal mar- 

 gin obliquely truncated, ventral margin rather con- 



Species 1. (Mus. Cuming in Brit.) 

 Mycetopus soleniformis. Mi/c. ie-dd cyUiidniced, 

 (doiigald, mbrrifiilnlcrd, medio coarclaid, itdiis pal- 

 lida ; latere aidico late, hiante, rotiindalo, puido hre- 

 rinre : latere pontico aiigidalo, paido hiante, margine 

 teriiiimdi tnnicato, laterali decUci, medio deprenw, 

 hiargiiie cardinali recto, veidrali coiicavo. 

 The soLENiroivM Mycetopus. Sliell cvliudi-ical, clon- 



D'OliBlGNV, Voyage dans rAnu'rique Meridionalc, pi. iVi . 



AiKiduii loiiginuiii, Spix. 

 Uah. River Amazon, Chicjuitos, Bolivia. 



The shells of this species vary greatly in the prnpor- 

 tions of their parts, some specimens in the D'Orbignjan 

 collection being little more than half the width of others 

 in proportion to their length. The posterior ventral mar- 

 gin is slighllv convex in some eases. 



