346 TRANSACTIONS LIVEErOOL BIOLOGICAL SOCIETY. 



form one of the most familiar objects of the tioisam and 

 jetsam thrown up on our shores. 



The individual capsules are flattened on tlie under 

 side, aud wheu seen from above they are oval in shape. 

 A clearer idea of their appearance can be best obtained 

 by reference to tlie hgures. The wall is made of two 

 layers of membrane, both of which are perfectly smooth 

 on the ventral Hattened side (fig. 61). The outer wall 

 appears crinkled on the convex surface (fig. 65). This is 

 due to the presence of delicate hbres. v.'hich, however, 

 are of short length and often branch. 



The outer walls of adjacent capsules are continuous, 

 so as to join the yellow capsules together in masses. 



The eggs of the gastropoda are not alwa3's laid in 

 chitinous capsules of this kind, there being other modes, 

 i.e. (a) free without any protecting capsule, [l)) with 

 calcified membrane, (c) deposited in ribbons (Opistho- 

 branchs), and (d) in gelatinous masses. The capsules 

 of the whelk have been supposed by most zoologists 

 to be formed by the oviduct, and the most distal or 

 uterine portion of that tube is extremely glandular. 

 Cunningham, however, in 1899, in a letter to " Nature," 

 announced that the ep;^^ capsules of Buccinitni and Mure.v 

 were formed by a secretion from the anterior groove of 

 the foot. The eggs must therefore pass round from the 

 pallial cavity, imbedded in a quantity of gelatinous 

 material, to the under surface of tlie foot. Then in the 

 groove they become surrounch'd by the cliitinous ca])s\ih\ 

 Cunningham's discovery luis apparcnily never been 

 noticed, and no information on tlio subjccl appears in 

 the textbooks. Not only does liuccinuin form its ( gg 

 capsules in this way, ])ut ilie same thini;- a|)plies to 

 I'ti r jnira , ;ind I'clsencc)- has artuallv found fhc ca])snles 

 in 1 he vcnl i al pcchil ghiiid. 



