t6o journal ok CONCHOLOGY, vol. 15, NO. 5, JANUARY, I917. 



vfhite, roundly ovate, very thin shelled, finely granular, fragile, and 

 lightly shining. This snail is usually found at the roots oi Phormiutn, 

 forming regular nests, eggs and young snails in the centre, and out- 

 side these there is generally a circle of dead shells. 



In Pariiila^ reproduction seems to be ovoviviparous. The upper 

 part of the oviduct contains eggs with a calcareous shell, which, as 

 they mature, become dissolved and consumed by the embryos. 

 Pilsbry describes the egg of P. bellula Hart, as shortly-oval, matt- 

 white, quite smooth under a lens, and measuring 3 x 2-5 mm. A speci- 

 men of P. ganymedes Pfr., from Society Islands, in my collection, 

 contained an egg which is oblong-oval, white, and measures 3 '5 x 2*5 

 mm. ; and I have a set of eggs of the sinistral P. caftaiis Mss., from 

 Upolu (ex Godeffroy Collection), which are white, elliptical, and 

 measure 4*5 x 3-5 mm. 



In the family Achatinidce the number and variety of species is very 

 great, and the variation in the eggs of such as are known is corres- 

 pondingly so. The African species are classified, provisionally, by 

 Pilsbry, under the principal groups Achatina, Cochlitoma, and Archa- 

 chatina^ but many are inadequately known anatomically, especially 

 some of the commonest West and South African species. In Acha- 

 tina the reproduction is oviparous, the eggs small, numerous, oval, 

 calcareous, pale yellow, and the adult shells have a correspondingly 

 small dome. Gibbons states that a specimen oi A. panthera Fer., 

 from Mozambique, whilst in his possession laid 196 eggs. Some 

 eggs of this species which I have from the Gibbons Collection, are 

 oval, mustard-yellow, thin shelled, 6x5-5 mm. Von Martens found 

 dull, pale yellow eggs 6x5 mm. in A.fulminatj'ix Mts. from Tangan- 

 yika. A. jacohi Da Costa, from Salisbury, Rhodesia, has spherical, 

 yellow eggs, 5x4 mm. diameter. A. achatina L. ( = ^4. variegata 

 Lam.) from West Africa, has oval eggs : a specimen I have is tawny 

 in colour, and measures 8 x 6"5 mm., but the colour may be due to 

 staining, as the egg was taken from the dried-up animal. I have eggs 

 oi A. fulica Fer., from Madagascar, which are dull yellowish-white, 

 very elongate-oval, and measure 5 x 375 mm. In the sub-genus 

 Leptocala the eggs differ in colour from those of Achatina in being 

 dirty-white; those of L. ptilchella Mts. measure 4x5 mm. In Coch- 

 litoma the reproduction is ovoviviparous, the young shells at birth 

 being considerably larger than those hatched from species of Achatina 

 which have equally large shells when adult. Semper found sixty un- 

 developed eggs with calcareous shells in a specimen of the South 

 African C. zebra Brug., the smallest 3 mm., the largest 6 mm. long, 

 together with twenty-five embryos which had broken out of the cgg- 



s^^^^^- (To be concluded). 



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