108 RAMANAN : ON THE HABITS OF AMPULLARIA. 



would seem to indicate that the results, of one of them at least, were not 

 based on a prolonged and close examination of its life-habits. At the 

 same time, my observations on the breathing, sinking, and floating habits 

 of A. (/lobosa, Swains., disclose facts which seem to be quite novel as regards 

 the genus, for I have not found any writer making even a remote reference 

 to them. 



Description of A. globosa, Swains. 



I have thought it might be useful to give a description of the external form 

 of the animal, chiefly because I have not seen a description elsewhere. 



Body of a light brownish grey colour above, dotted over with spots of 

 a brilUant black, edged with glowing yellow, and of a pale bluish or slate 

 tint below. Muzzle stout and conspicuous, produced into two long 

 tentacular processes. Tentacles proper, very long and tapering. Eyes 

 prominently stalked. Two nuchal lobes, the left one forming a long 

 siphon at the animal's pleasure. Respiratory cavity divided by a septum, 

 the right chamber having a large monopectinate branchia, while that 

 in the left is vestigial. The left chamber functions mainly as a pidmonary 

 sac, when the animal indulges in aerial respiration. The shape of the 

 foot is roughly triangular, with the angles bevelled and the apical portion 

 situated posteriorly. The foot-sole is of a dirty yellowish hue. 



"Respiratory and Locomotory Habits, Etc. 



About every twenty minutes or so, the animal crawls to the surface from 

 the bottom of the aquarium, '''' feeling its way for the air above the water- 

 level by its long, lashing, tapering tentacles. When within an inch from 

 the surface, it extends the siphonal tube formed by the curling over of its 

 left nuchal lobe '■*', thus bringing the orifice of the tube just above the 

 water. Gradually and almost imperceptibly the orifice expands, until 

 at last it comes to have a diameter of 15 millim., and concurrently with 

 the expansion, the tube itself gradually shortens, and the aperture in the 

 centre of the dividing wall between the lung and gill-sacs opens. The 

 nuchal lobe thus diminishes in length, and after attaining the utmost 

 limit of its expansion in breadth, unfolds in such a manner that it assumes 

 the shape of a semi-circle, forming only the lower half of the rim of the 

 siphonal orifice, Avhile the otlier half of the rim is provided for 

 by the basal part of the peristome, the body of the tube itself consisting 

 solely of the pallial lobes. It is curious, that this phenomenon is not 

 mentioned either by Semper or by Bouvier and Fischer. From what 

 they state, one would be led to understand that the siphonal tube under- 

 goes no change at the surface beyond elongation and amplitude. On the 



3. My Aquarium was a small glass tank •??! feet square. 



4. In discussing the breathing habits of A. insulorum, d'Orh., Prof. Semper tells us that the 

 elongated tube is formed by an incurving of the mir;.;iii of the mantle. If he means bj- mantle, 

 the pallial lobes ns distinct from the cervical lobes, the observation is not applicable to our Madras 

 species. Vide Semper: Animal Life, pp. il% et seq. Of course iho pulmonary chamber which 

 beconies the main part of the lube at a later stage, is made up of the pallial lobes. 



