276 MANUAL OF THE MOLLUSCA. 



Animal with the mantle-lobes open ; body large, oblong, projecting back 

 wards ; no trace of a foot ; palpi large, semi-oval ; gills sub-equal, plaitec 

 united posteriorly, and to the body and mantle. 



Distr. R. Nile, from 1st Cataracts to Fazool;* R. Senegal. 



MULLEUIA, Ferussac. 



Dedicated to Otto Frid. Miiller, author of the " Zoologia Danica." 



Type, M. lobata, Fer. Syn. Acostsea (Guaduasana) D'Orb. 



Shell when ysung free, equivalve, Anodon- shaped, with a long and pro 

 minent ligament, and two adductor impressions : adult irregular, inequivalve 

 attached by the right valve ; umbones elongated, progressively filled up wit 

 shell, and forming an irregular ' talon" in front of the fixed valve ; epider 

 mis thick ; ligament in a marginal groove ; interior pearly, muscular impres 

 sion single, posterior. 



Distr. R. Magdalena, near Bogota, New Granada. 



Mr. Isaac Lea has determined the identity of Mulleria and Acostcea b) 

 examination of Ferussac's type, and the suite of specimens, of different ages 

 in the collection of M. D'Orbigny. f 



SECTION B. SIPHONIDA. 



Animal with respiratory siphons ; mantle-lobes more or less united. 

 a. Siphons short, pallial line simple ; Integro-pallialia, 



FAMILY VII. CHAMIP.E. 



jS/^/Hnequi valve, thick, attached; beaks sub-spiral; ligament external; 

 hinge-teeth 2 in one valve, 1 in the other ; adductor impressions large, 

 culated ; pallial line simple. 



Animal with the mantle closed ; pedal and siphonal orifices small, sub 

 equal ; foot very small ; gills two on each side, very unequal, united pos 

 teriorly. 



CHAMA (Pliny) L. 



Ex. C. macrophylla, PI. XVIII. figs. 8, 9. Syn. Arcinella, Schum. 



Shell attached usually by the left umbo ; valves foliaceous, the uppei 

 smallest ; hinge-tooth of free valve thick, curved, received between two teeth 

 in the other ; adductor impressions large, oblong, the anterior encroaching 

 on the hinge-tooth. 



Animal with the mantle-margins united by a curtain, with two rows o: 

 tentacular filaments ; siphonal orifices wide apart, branchial slightly promi- 

 nent, fringed, anal with a simple valve ; foot bent, or heeled ; liver occupying 

 the umbo of the attached valve only ; ovary extending into both mantle- 

 lobes, as far as the pallial line ; lips simple, palpi small and curled ; gills 



* The " fresh- water oysters" discovered by BRUCE. 

 t The only specimen of Mulleria in England was purchased many years ago by 

 Mr. Thos. Norris, of Bury, for 2Q. 



