1909.] N. Annandale : A 71 Anemone without tentacles. 161 



those implied in their change of shape. They were, however, 

 practically of the same specific gravity as that of sea-water on the 

 surface of the Bay of Bengal. There can be little doubt that they 

 had been carried by the currents and the winds, so far as the latter 

 affected the water on the surface. The individuals cast up on the 

 beach at Puri had evidently been driven through the surf -line, prob- 

 ably by a stiff breeze acting on the surface of the water. It is 

 noteworthy that though they were numerous on February ist, not 

 a single specimen was found on January 29th, 30th, 31st, or on 

 February 2nd. 



It is well known that surface animals without independent 

 means of progression often occur in vast shoals of the same species 

 This fact was well illustrated at Puri on the occasion on which 

 Anactinia was found. On Januar^^ 29th and 30th large numbers 

 of a species of Porpita were washed ashore. Among them were a 

 few specimens of a species of Velella. On January 31st, however, 

 the relative proportions of the two genera were reversed, Velella 

 becoming abundant and Porpita scarce. On February ist both 

 were scarce, but Anactinia was abundant, while on February 2nd, 

 after a sharp shower of rain during the night, very few surface, 

 organisms of any kind were found on the beach. 



I can find no trace of food in any of the specimens of Anacti- 

 nia I have dissected. 



Systematic Position. 



The arrangement of the mesenteries, the position of the longi- 

 tudinal muscles of the column and the presence of a single ciliated 

 groove running down the stomodseum are all facts which link 

 Anactinia with Cerianthus, and there can be no doubt that it 

 should be placed in the same order as that aberrant form. The 

 absence of tentacles, however, as well as other less important 

 differences, point to a very distinct separation between the two 

 genera. Anactinia in all probability is a member of the order 

 Cerianthidea which has become modified in accordance with a 

 pelagic life. 



It is worthy of remark in this connection that the larvae of 

 Cerianthus are pelagic in habit but settle down at the bottom before 

 they have developed many tentacles. The young of Actiniaria, 

 however, as also those of some other Coelenterates, appear to pro- 

 vide for their own distribution mainl}' in two different ways. Those 

 of Sagartia troglodytes , Actinia mesembryanthemum and some other 

 common viviparous species, for example, retract the tentacles 

 with which they are provided at birth, close their mouths and, 

 being of almost the same specific gravit}^ as the water in which 

 they live and not having any projecting structures on their sur- 

 face, are rolled over and over b}^ the slightest movement in the 

 water and are so carried for considerable distances. The 3'oung 

 of Metridium schillerianum, of Cerianthus and of some species of 

 Hydra, on the other hand, expand their tentacles to the utmost 

 (so as to cover as large a superficial area as possible) and float on 



