No. 6 (I92T) common MOLLLISCS OF SOUTH INDIA 



145 



lumpy and very soft to the touch, with a thin and much reduced 

 transparent ear-shaped brown shell all but covered by the mantle 

 and further protected by two fleshy side lobes of the foot. The 

 stumpy head is armed with two pairs of tentacles, the hinder the 

 larger. The middle region of the body rises high with a humpy 

 back ; behind, the broad flat foot passes into a distinct tail. In 

 colour Aplysia is mottled and spotted a dirty purplish brown with 

 points of white scattered throughout. 



They are common in most parts of the world and the Indian 

 species is almost indistinguishable from the British, and equally 

 abundant in weedy shallows in bays and the seaward ends of 

 backwaters. They vary greatly in abundance from year to year; 

 sometimes they appear along the margin of the sea in multitudes; 

 in other seasons scarcely one is to be found. When handled these 

 animals discharge a large quantity of purple fluid from under the 

 mantle. This secretion is quite harmless but is undoubtedly protect- 

 ive, for it discolours the water for a considerable distance around, 

 alarming to any fish that may seize one of these animals. The 

 odour too is unpleasant, and to some people distinctly nauseous. 

 Aplysia deposits its ova in long greatly tangled cords, of con- 

 siderable total bulk, the colour pale brownish pink (fig. 33). In India 

 the spawning time (Ennur and Tuticorin' is February and March. 

 It is at this time that the animals are particularly gregarious. A 



--.-' '■ 



Fig. 32. l^ife appearance of the Plumed Sea-hare {Notarchus) from Eanur. 



Natural size. 



member of another genus extremely closely related in form, size 

 and colour is Notarchus, marked oft" distinctly from Aplysia by the 

 presence of long filaments, the larger dendritic, scattered thickly 

 over the whole upper surface of the body. Whether this is in any 



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