ADAMS : NOTES FROM THE ARGENTINE AND URUGUAY. 317 



elevated parts of the country towns are built above the flood limit. 

 The country is mostly under cultivation, but viscachas and tuco- 

 tucos are often as common as rabbits and moles in England. On 

 the open country no land species of moUusks are to be found, but 

 the swamps proved fruitful and interesting, though rather tiring 

 to explore. 



It is somewhat of a handicap to one's enthusiasm to have to 

 struggle through a tangled mass of prickly scrub on a very hot day, 

 ankle deep in mud and ooze, encumbered with a long hooked stick 

 for raking the great snails towards one out of the slimy mud, a 

 revolver, numerous tins and often pockets full of heavy AmpitUaricB^ 

 eaten alive all the time by mosquitoes and biting flies — the mosqui- 

 toes here are as active in the day as at night ; keeping a sharp 

 look-out for poisonous snakes, many of which I killed and preserved. 

 This sort of country alternates with a barren plain, where it is im- 

 possible to sit down for miles, owing to cactus and ants. However, 

 I enjoyed it, and secured a fine set of the following species : — 



Ampullaria tnsularuni d'Orb. — Very common at Colastine, San 

 Nicolas, and Arguerich. 



Ampullaria scalaris d'Orb. — Common at Colastine, Santa Fe, and 

 Rosario. 



Marisa cornu-arietis L. — Moderately common at Colastine. 



Paludina spixii d'Orb. — Abundant at Colastine, San Nicolas, and 

 Arguerich. 



Castalia ambigua Lam. — Local at Colastine. 



Besides these, I found two species of Plaiwrbis, a Fali/difia, a 

 Paltidestrifia, and a (?) small Buiimuhis, none of which I have been 

 able to identify. If any specialist in these genera can help me, I 

 shall be glad to present him with the specimens. 



Two- and three-denticled forms of Jaminia muscorum L. — On September 

 5th last, whilst hunting with Mr. W. G. Clarke for neolithic flint implements 

 on the warrens and "breaks"' to the west of Thetford, Norfolk, I came across 

 a tract of land very similar in character to Lingheath Common, Brandon, where 

 the tridentate form of laniinia is found. The soil is chalky and full of shallow 

 depressions — the remains of pits made by the flint-diggers in getting material for 

 the gun-flint industry. On looking under the stones and lumps of chalk that 

 lay strewn about, we found half-a-dozen specimens o{ Jaun'via iiiuscorii^n, four 

 of which were the variety digrafja/a and two were tridentate. The spot is 

 near St. Helen's Well on the western border of the parish of Thetford St. Peter, 

 and about four miles east of the Brandon site. — A. Mayfield {/■iead before the 

 Society, Sept. 9th, 1908). 



