after the most anxious examination of numerous specimens that 

 I concluded to unite the various synonyma above enumerated, to 

 the description of tins species. The British varieties are well 

 known ; of the foreign varieties, var. Heildreickii is found in the 

 Lago di Garda, Italy; var. zebrina, at Montpellier; var. Polapo- 

 nensis, at Morea; var. uumidica, in the " Vallee de Tiri a Oray;" 

 and several varieties are found in Sicily ; var. mittreana is found in 

 France ; var. thermalis in hot springs in the Pyrenees ; var. sanloa 

 is from Sardinia ; and var. trifasciata in the ditches at Milan. 



27. Neritina transversalis (pi. cxiv. f. 151, 152), Ziegler. 

 Rosmasler, Icon. pi. 7. f. 121. 



N. testa N.fluviatili simili, sed magis ovali; labio interno sub- 

 calloso ; colore cceruleo, trifasciato. 



Of a more simply oval form, with generally a smaller spire, and 

 the left edge of the inner lip slightly callous. The outer lip does 

 not exhibit the same tendency to spread at the lower part. The 

 colour is ashy, with three very obscure dark transverse bands. 

 Operculum of a reddish colour. 



28. Neritina succinea (pi. cxiv. f. 153, 154), Recluz, Rev. 

 Zool., 1841, p. 343. 



N. testa N.fluviatili simili, sed spira complanata; colore suc- 

 cineo. 



A minute, amber-coloured shell, of the general form of N. 

 fluviatilis, but with the spire flatter. 

 Guadaloupe. 



29. Neritina meridionalis (pi. cxv. f. 187-190), Philippi, 

 Enum. Moll. Sicil. p. 159, no. 3. pi. ix. f. 13 var. N. inqui- 

 nata, Morelet, var. f. 189. N. lutescens, var. N. Philippii, 

 Recluz, var. N. Boetica, Lam. Anim. s. Vert. vi. p. 188. N. 

 Moreleti, Recluz. N. elongatula, Morelet. 



N. testa transverse subelongata, lsevi, varie picta vel nigra ; 

 spira exsertiuscula ; apertura semilunari ; labio interno lsevi, com- 

 planata ; labio extern o superne subdeclivo. 



Although some specimens of even the British variety of N. 

 fluviatilis approach this species in form, yet the prevailing form 

 of the two are different, this being less elongated, and having the 

 upper part of the outer lip much more sloping. On examining 

 a large number of specimens I fully concur with M. Philippi in 

 uniting several of the above synonyma with this species ; and I 



