Notices of New Books. 7301 



almost opaque, yet during the whole period they appeared perfectly 

 at ease, and even increased their number by fissiparons division. It 

 is the frequent habit of the species to crawl up the perpendicular side 

 of the tank which it inhabits, till it reaches the water's edge, a situa- 

 tion which seems particularly grateful to it, for there it remains from 

 week to week, daily (or ralher nightly) projecting its columnar form 

 in a horizontal direction, at the very surface, and then expanding its 

 beautiful frills, so that the air bathes a part both of its body and its 

 tentacles. 



" I have never seen this anemone increase its kind by proper gene- 

 ration, that is, by the discharge of ova or of young. But no species 

 more freely increases by spontaneous division. When a large indi- 

 vidual has been a good while adherent to one spot, and at length 

 chooses to change its quarters, it does so by causing its base to glide 

 slowly along the surface on which it rests, the glass side of the tank 

 for instance. But it frequently happens that small irregular fragments 

 of the edge of the base are left behind, as if their adhesion had been 

 so strong that the animal found it easier to tear its ovfn tissues apart 

 than to overcome it. The fragments so left soon contract, become 

 smooth, and spherical or oval in outline, and in the course of a week 

 or fortnight may be seen each furnished with a margin of tentacles 

 and a disk, — transformed, in fact, into perfect though minute ane- 

 mones. Occasionally a separated piece, more irregularly jagged 

 than ustial, will, in contracting, constringe itself, and form two 

 smaller fragments, united by an isthmus, which goes on attenuating 

 until a fine thread-like line only is stretched from one to the other; 

 this at length yields, the substance of the broken thread is rapidly 

 absorbed into the respective pieces, which soon become two young 

 Dianthuses. 



" It is to this tendency to spontaneous division that I would attri- 

 bute the frequent occurrence in this species of monstrosity, such as 

 two disks uniting into a single column. This is very common. Dr. 

 Johnston supposes that such cases are produced by the coalescence 

 of two individuals which happened to be in contact, and he accounts 

 for its frequency by the gregarious habit of the species. The possi- 

 bility of two individuals thus uniting remains, however, to be proved ; 

 while the fissiparons habit, which is patent, is quite sufficient to pro- 

 duce the phenomenon. 



" I have been informed of a case in which a young one was pro- 

 duced by gemmation from the base of the adult, without any previous 

 separation of the fragment." 



