Limnea. MOLLUSCA. PULMONIFERA. 275 



Mont. Test. Brit. 373, tab. xvi. f. 3 — L. ovatus, Drap. Moll. 50 — In 

 ponds and rivers. Common. 

 Length seldom exceeding an inch ; translucent, with minute lines of 

 growth, and longitudinal wrinkles.— This shell, every where abundant, exhi- 

 bits considerable differences in its mode of growth and forms, according to the 

 places it inhabits, and has given rise to the construction of many spurious 

 species. 



— 112. L. auricularia. — Whorls four, the three first minute, 



flat pointed. 



Buccinum pellucidum, subflavum, quatuor spirarum, mucrone acutissi- 

 mo, testae apertura omnium maxima, List. An. Ang. 139. Conch, 

 tab. 123, f. 22 — H. auricula, Linn, Syst. i. 1250. Penn. Brit. Zool. 

 iv. 138. Mont. Test. Brit. 375, tab. xvi. f. 2 In stagnant pools. Eng- 

 land. 



Length about an inch, thin, subpellucid, striated across, and wrinkled lon- 

 gitudinally ; mouth wide ; the outer lip semicircular. — This species is often 

 confounded with the preceding, from which it differs in the apex being more 

 pointed, the three first spires more minute, and the outer lip more expanded. 



113. L. glutinosa. — Whorls three; the two first minute, the 

 last ventricose, and diaphanous. 



Bucc. glut. Mull. Verm. ii. 12G — Helix glut. Mont. Test. Brit- 379, 

 tab. xvi. f. 5. — In ponds. England. 



Length about half an inch, thin, fragile, glossy, nearly smooth ; aperture 

 oval, without the fold on the pillar-lip. Animal large in proportion to its 

 shell ; of a yellow colour. 



114. L. lutea. — Whorls scarcely three; the last large in pro- 

 portion ; pillar-lip spreading. 



H. lutea, Mont. Test. Brit. 380, tab. xvi. f. 6. Turt. Conch. Diet. 69. 

 Shepp. Linn. Trans, xiv. 169. England. 



Length half an inch, suboval, subpellucid, yellow, smooth, apex obtuse, 

 aperture patulous, oval. — The two authors first quoted seem to consider this 

 , as a sea-shell; while the last states that he has taken it in abundance at 

 Winthorpe, on the banks of the Trent, after a flood, and at least thirty miles 

 above its junction with the salt-water. He adds, " it probably inhabits the 

 depths of rivers." 



115. Assiminea Grayana. — Dr Leach sent me, several years 

 ago, a shell, from Greenwich marshes, constituting " a new fresh 

 water genus, 1 '' under the title Assiminea Grayana. The lip is 

 thickened on the pillar, and reflected over the cavity, but is des- 

 titute of the oblique fold ; and the lip does not extend over the 

 body-whorl. The colour is brown ; the whorls six in number, 

 conical, regularly increasing in size, glossy, with minute lines of 

 growth. Length about T a ths of an inch. 



EXTINCT SPECIES. 



1. L.fusiformis — Subfusiform, smooth; sides of the spire nearly straight ; 

 aperture narrow, half the length of the shell, Sower. Min. Conch, tab. 169* 

 £ 2, 3 — Fresh water formation, Isle of Wight. 



S 2 



