i6i 



JOURNAL OF CONCHOLOGY. 



Vol. 15. APRIL, 1917. No. 6, 



ON THE CALCAREOUS EGGS OF TERRESTRIAL 

 MOLLUSCA. 



( Concluded from p. i6o). 



(Presidential Address delivered at the Annual Meeting, October- 14th, igiE 



By ROBERT STANDEN, 



Assistant-Keeper of the Manchester Museum. 



C. granulafa (Krauss) from Natal, has pale yellow, oval eggs, 

 9 X 7'5 mm. ; those of C. varicosa Pfr., from the Cape, are elongate- 

 oval, yellowish-white, and measure 15 x 10 mm. ; C. seinidecussata 

 Pfr., from Natal, has oval, yellow eggs, 10x8 mm. C. viofginafa Sw. 

 is said to deposit its eggs in the axils of branches of trees, but I have 

 eggs from Fernando Po which are stated by their collector to have 

 been deposited on the ground at the foot of trees. They are oblong- 

 oval, yellowish-white, and measure 19 x 14-5 mm. The large egg, 

 25 X 17 mm., described and attributed to A. achatina L. by von 

 Martens, probably belongs to A. marginata or some other large- 

 domed species. 



In Archachatina, the obtuse dome of the shell, caused by the great 

 size of the protoconch developed in a very large egg, separates it at 

 once from the small-domed Achatina, and it also differs from Cochli- 

 toma in the more ample protoconch and oviparous reproduction. 

 The largest eggs produced by any member of this family appear to be 

 those of ^. bicarinata Brug., from Sao Thome. They are from three 

 to five in number, varying in size from 14 x 20 mm, to 19 x 17 mm., 

 are a beautiful citron-yellow in colour, and have a shell 3 mm. thick. 

 A. purpurea (Gmelin) has very large yellowish-white eggs measuring 

 18 X 1 2 "2 5 mm. 



The eggs of Ho morns castanea Mts., from East Africa, are elongate- 

 ovate, and 5 mm. in length ; those of H. pileatus Mts., according to 

 d'Ailly, are nearly spherical, 2 mm. in diameter; a specimen of 

 H. manboieiisis (Smith) examined by Smith contained an egg, 5 mm. 

 in length, elongate-ovate in shape. In the West African Pseudo- 

 glessula the eggs are markedly oblong, and lie obliquely in the 

 oviduct. P. rettfe?-a Mts., frc 111 Cameroon, has pale yellowish, white 

 eggs, 4 X 275 mm. ; in P. sjoslcdii d'Ailly, they are pure white, 6x3 



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