232 



ON THE SPAWN OF 



VI. 



ON THE SPAWN OF TTJRBINELLA RAP A, 



THE CHANK-SHELL. 

 The specimen which forms the subject of this brief memoir 

 was presented to the Museum by E. M. Adam, Esq., 

 Deputy Commissioner of Inland Customs, on special duty, 

 and was procured by him at Tuticorin. Although not, 

 perhaps, new to science, it is still, I think, sufficiently 

 rare and curious to merit its being figured and described in 

 the Society's journal. As indicated in the heading to 

 this notice it is the spawn of the mollusc Turbinella rapa, 

 the famous and sacred Konch or Chank-shell of which a 

 figure is given in Plate I. The Turbinella is one of the 

 carnivorous gasteropods and the sexual organs are in 

 distinct individuals. Owing to its predatory habits it lives 

 in deep water, where food is abundant, and accordingly its 

 spawn is also deposited there, so that the young on their 

 escape from the egg may be able to gratify their zoophagous 

 tastes, and get on in the world. The envelopes of the eggs 

 of the carnivorous gasteropods differ much in form, but they 

 all agree in consisting of tough membranous capsules, 

 arranged singly or in groups, and in each of the capsules 

 containing a large number of germs. As will be seen by a 

 reference to Plate II, Fig. 1, the spawn of the Turbinella 

 consists of a series of sacs or oviferous receptacles, the 

 transverse markings in the figure indicating the dimensions of 

 each capsule. In the fresh state the membranous walls of the 

 sacs are pliable, although tough and strong, but when dried 

 they become somewhat horny ; and it will be observed that 

 during the drying process the spawn figured in Plate II has, 

 from the irregular shrinking of the two sides, become curved 

 and twisted so as to have somewhat the appearance of a horn. 

 On careful examination it is found that the several pouches 



