274 MANUAL OF THE MOLLtJSCA. 



Norway, Nortli Britain, Tierra-del-Fuego. In 20 — IOC fathoms 

 water. 



Fossil, in the glacial formations of North Britain. 



BiMULA, Defrance. 



Etymology, diminutive of rima, a fissure. 



Synonym, Bimularia. 



Recent type, E. Blainvillii, PL XI., Pig. 4. 



Shell thin and cancellated, with a perforation near the anterior 

 margin. 



Distribution, several species found on sandy mud at low water, 

 or dredged in from 10 — 25 fathoms. Philippines (Cuming). 



Fossil, 3 species. Bath oolite — coral rag. Britain and France. 



Emaegintjla, Lam. 



Etymology, diminutive of emarginata, notched. 



Type, E. reticula, PL XL, Pigs. 5 and 6. 



Shell oval, conical, elevated, with the apex recurved ; surface 

 cancellated ; anterior margin notched. Muscular impression 

 with recurved points. The nucleus (or shell of the fry) is spiral, 

 and resembles scissurella. The anterior slit is very variable in 

 extent. The animal of emarginula (and also of puncturella) has 

 an isolated cirrus on the back of the foot, perhaps representing 

 the operculigerous lobe. (Forbes.) Lingual dentition, median 

 teeth sub-quadrate ; laterals 4, oblong, imbricated ; uncini about 

 60, the first large and thick, with a lobed hook, the rest linear, 

 with serrulated hooks. (Loven.) 



Distribution, 40 species. AVest Indies, Britain, Norway, 

 Philippines, Australia. Eange from low water to 90 fathoms. 



Fossil, 40 species. Trias — . Britain and Prance. 



Sub-genus. Hemitoma, Sw. 



Type, E. octoradiata (E. rugosa, PL XL, Pigs. 7 and 8). 



Shell depressed, anterior margin slightly channeled. 



Parmophorus, Blainville. Duck's-bill limpet. 



Etymology, parme, a shield, and phoreus, a bearer. 



Type, P. australis, PL XL, Fig. 9. 



Synonym, Scutus, Montf. 



Shell lengthencd-oblong, depressed ; apex posterior ; front 

 margin arched. Muscular impression horse-shoe shaped, elon- 

 gated. The shell is smooth and white, and permanently covered 

 by the reflected borders of the mantle. The animal is black, 

 and very largo compared with the shell ; its sides are fringed 

 with short cirri, and its eyes sessile on the outer bases of thick 



