80 Journal of the Astatic Society of Bengal. [FeTDraary, 1907. 



« 



to agree "witli the diagnosis after a few days. In eacli of the 

 specimens several of the vesicles tore two otoliths; but this 

 was also the case in some of the specimens examined by the 

 ^anthor of the species, who susrcrested that the phenomenon was 

 due to twinning. Such vesicles are considerably larger than 

 those which bear one otolith. I also found the " warts or tuber- 

 cles " noted by Mr. Browne between some of the tentacles and 

 have no doubt that they are, as he suggests, young tentacles in 

 the course of development. Not only does their structure sup- 

 port this view, but the spaces in which they occur are also dis- 

 tinctly greater than* those usually occurring between two tentacles. 

 Although one of Mr. Paiva's specimens measures about 20mm. 

 in diameter, none of them are sexually mature, the gonads being 

 represented in the youngest specimen (pi. II- fig. 5) by a linear 

 swelling on tlie upper part of the radial canals. In an older 

 specimen they extend further down towards the margin. 



Since the above was written I have had an oppoiiiunity of visit- 

 ing Port Canning (on December 3rd), accompanied by Mr. Paiva. 



We found the Medusae in large numbers in the pool in which tliey 

 had already been taken, the individuals measuring from less than 

 a millimetre to about twenty millemetres in diameter, but none 

 being sexually mature. In life they were colourless and somewhat 

 more globular than the specimen figured, owing to the umbrella 

 being contracted at the base ; younger individuals being slightly 

 deeper in the bell than older ones. They were sluggish in their 

 movements and their umbrellas only contracted at intervals, gen- 

 erally doing so several times over before a period of quiescence. 

 They were most abundant in the centre of the tank, which was 

 there free from weeds. An interesting discovery due to this visit 

 was that of the hydroid stage of Irene, which was found growing 

 on weeds at the edge of the pool. There could be little doubt 

 as to its identity with the Medusa, as the pool was a small one and 

 no other Hydroid could be found ; but it has not yet been possible 

 to trace the life history. A single Medusa was taken which had 

 just been liberated. It had four stout, tapering tentacles, a feebly 

 developed umbrella and a relatively large manubrium. Unfor- 

 tunately it died and disintegrated before a complete examination 

 could be made It agreed in every respect with perfect Medusse 

 in the gonotheese which had not yeb been set free, and was found 

 moving slowly by means of its tentacles among the weeds. The 

 following is a description of the hydroid : — 



Colony minute, barely visible to the naked eye ; hydrothiza 

 delicate, recumbent, closely adhering, branching in a horisKontal 

 plane, giving rise at considerable intervals to upright hydrotheciBB 

 and gonothecse ; the whole exoskeleton transparent and colourless. 

 Hydrothecje with short, irregularly ringed pedicels, which are 

 about one-seventh as long as the cup ; the cup cylindrical or broader 

 above, three times as long as broad, closed above by an operculum 

 formed of a number of convergent pieces. Gonothecse larger than 

 hydrotheca? and with a much longer pedicel, club-shaped, opening 

 above by a single aperture. Polyps, when fully expanded, at least 



