]30 



MANUAL OF THE MOLLUSCA. 



branchial plume single, long; lingual ribbon linear; teeth single, hooked, 

 denticulated ; uncini 3, the first transverse, 2 and 3 claw-shaped. 



Fig. 80.* 



Distr., 3 sp. Labrador, Norway, Brit., Medit. "W. Africa. Range, 

 100 fins. 



Fossil ; see Pteroceras and Eostellaria ; above 200 species, ranging from 

 the lias to the chalk, probably belong to this genus, or to genera not yet 

 constituted. 



STRUTHIOLARIA, Lam. 



Etym.) struthio, an ostrich (-foot), from the form of its aperture. 



Type, S. straminea, PL IV., fig. 6. 



Shell turreted ; whirls angular ; aperture truncated in front ; columella 

 very oblique ; outer lip prominent in the middle, reflected and thickened in 

 the adult; inner lip callous, expanded; operculum claw -shaped, curved in- 

 wards, with a projection from the outer, concave edge. 



Animal with an elongated muzzle ? tentacles cylindrical ; eye-pedicels 

 short, adnate with the tentacles, externally ; foot broad and short, (Kiener.) 



Distr. , 5 sp. Australia and New Zealand ; where alone it occurs sub- 

 fossil. 



FAMILY IV. MELANIAM. 



Shell spiral, turreted; with a thick, dark epidermis; aperture often 

 channelled, or notched in front; outer lip acute; operculum horny, spiral. 

 The spire is often extensively eroded by the acidity of the water in which the 

 animals live. 



Animal with a broad non-retractile muzzle ; tentacles distant, subulate ; 

 eyes on short stalks, united to the outer sides of the tentacles ; foot broad and 

 short, angulated in front ; mantle-margin fringed ; tongue long and linear, 

 with a median and 3 lateral series of hooked rnulti-cuspid teeth. Often 

 viviparous. Inhabiting fresh- water lakes and rivers throughout the warmer 

 parts of the world. Only fossil in Britain. 



the 



Fig. 80. Aporrhais pes-pelecani, L., from a drawing by Joshua Alder, Esq 

 ;( British Mollusea." 



I 



