122 MADRAS FISHERIES BULLETIN VOL. XIV, 



big Egg Cowry {Ovum ovum) used in New Guinea and the islands 

 to the east as a personal ornament and as a decoration of everything 

 the natives value and more especially their boats. It is snow white 

 in colour and is a striking ornament when a number are worn as a 

 fillet round the forehead or hung like bells from the prows of canoes. 

 Smaller forms are common in Indian seas as commensals upon the 

 sea-fans (Gorgonids). Gorgonids are usually brown or yellow or red 

 and the little Ovula shells {Oviila formosa) always agree in colour 

 with their host's hue; a yellow Ovula is never found on a red 

 gorgonid, or a red Ovula on a yellow gorgonid. The colour of the 

 mollusc resides in the mantle only ; the shell is riot coloured. Even 

 more beautiful is a species of cowry living upon the cauliflower- 

 like Spongodcs — one of the soft corals. In this case the host is either 

 pink or orange in general colour, but this colour is confined mainly 

 to the terminal parts of the branches bearing polyps ; the main 

 stem and the branches are generally white. Hence the little cowry 

 that lives here has the mantle blotched yellow or red as the case 

 may be ; this obviously harmonizes with the general colour of the 

 host much better than if the mollusc were self-coloured. The foot 

 is narrow and admirably adapted for climbing along the round 

 stems of its host. In size these little commensal cowries seldom 

 exceed an inch in length. They are active in habits and get along 

 nearly as quickly as the red (or yellow) spotted commensal crabs 

 that have the same protective colouring and live the same life 

 among the branches of Spongodes. 



Of the Triton-shells none of the large species used as shell 

 trumpets in Polynesia and in the Mediterranean is seen in Indian 

 waters except in the Laccadives ; its place appears to be taken by 

 the chank or sankha {TurhineUa pirum). Small forms belonging 

 to the genus Rauclla are, however, common. These shells, known 

 in Europe as FrOG-SHELLS, are short and stout, with a strong 

 ridge or varix continuous along the whole length of each side of the 

 shell. The intervening space is tuberculated ; the lip corrugated. 

 They live in shallow water on rough bottom, and well deserve their 

 common name for they have an absurd likeness to a tiny tree-frog 

 squatting, head up, ready for a leap. Ranella foliata and R. 

 granifera are common species. 



The larger HELMET-SHELLS {Cassididac) are represented in 

 India by two species, the Great Helmet-shell, Cassis coniuta, and 

 the Red Helmet, Cassis rufa. The former is the heaviest and 



