376 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, plaited, 

 united posteriorly, and to the body and mantle. 



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



MuLLERiA, Ferussac. 



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



Ti/pe, M. lobata, Fe'r. Sijn. Acostsea (Guaduasana) D'Orb. 



Shell when young 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 with 

 shell, and forming an ii-regular '• talon" in front of the fixed valve ; epider- 

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

 sion single, posterior. 



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



]\Ir. Isaac Lea has determined the identity of Miilleria and Acostsea by 

 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 vAila. respiratory siphons ; mantle-lobes more or less united. 

 a. Siphons short, pallittl line simple ; Integro-paUialia, 



FAMILY VII. Chamib^. 



iS/j^/Hnequivalve, thick, attached; beaks sub-spiral; ligament external; 

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

 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. 



Cham A (Pliny) L. 



Ex. C. macrophylla, PI. XVIII. tigs. 8, 9. Si/n. Arcinella, Schum. 



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

 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 of 

 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 b}' Bruce. 



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

 Mr. Thos. Norris, of Bury, for £20. 



i 



