338 LAND AND FRESH-WATEll SHELLS. 



Amono-st the several forms which 1 obtained, three were named as 

 new varieties, var. vieridionalis from Santa Anna, vav. simhoana from 

 Simbo or Eddystone Island, and var. septentrionalis from the islands 

 of Bougainville Sti-aits, the localities of the two last varieties being- 

 only 80 miles apart. Mr. Smith remarks that this species is " subject 

 to considerable variation in size, colour, and form, ajjparently re- 



sultino- from difierence of habitat Whether these several 



varieties should take specific rank is questionable, for, although there 

 is a considerable difierence between the extreme forms, even in the 

 series of nearly one hundred specimens under examination, the 

 p-radual transition from one form to another is observable." 



Amongst the more singular in appearance of the land shells, I 

 may refer to the large Bulivius (B. cleryi) which I found on the 

 north coast of St. Christoval. It attains a length of four inches. I 

 was never able to get a living specimen, as they are said by the 

 natives to live in the foliage of the high trees. The specimens 

 which I obtained were empty shells which the natives of the Koofeh 

 district on the north coast of St. Christoval are in the habit of 

 throwing into heaps, each man when he picks up a shell thi^owing it 

 into the next heap he passes. I was unable to learn the reason of 

 this practice and the natives did not seem willing to tell me. . . . 

 Two other Bulimi I commonly met with. One was the pretty Bulinms 

 miltocJieilus (Reeve), which, wdien the animal is young and the shell 

 delicate, nas a greenish-yellow hue resembling the colour of the 

 leaves it feeds upon : as it grows older the shell becomes thicker and 

 stronger, and in proportion as there is less need for protective resem- 

 blance, the greenish-yellow hue fades away, leavinga dull white colour 

 behind. This species is found in St. Christoval and the adjacent 

 islands. The other Bulimus {B. foimaki, Homb. ' Jacq.) which I 

 found in Faro Island, Bougainville Straits, and which had been only 

 previously obtained at Isabel Island, attains a length of rather under 

 three inches. 



I come now to refer to the fresh-water shells of these regions. 

 Stated in their order of frequency, the Neritinoe, Melanice, and Navi- 

 cellcesive the common fres]>water shells of the e islands. The Neritince 

 were especially interesting to me. They abound in the streams : 

 some of them preferring the moist rocks above the water, others 

 finding tlieir home in the waters of a quiet pool, whilst others, like 

 the Navicelloi, prefer to buffet the full rush of the torrent. An 

 important feature with reference to these fre&h-water Nerites or 



