52 Anatomy of Sagartia Schilleriam [No. 1, 



It is usually stated that, when an Actinia is cut into a number of 

 pieces, each restores itself to a perfect animal. Though this kind of 

 propagation no doubt has its limit, I may, record, that experiments 

 made on some specimens of this species in general confirm the great 

 vitality and reproductive power of the Actiniacea. 



With the object of observing some of the ovaria, I once cut a speci- 

 men in two halves, and left one part of it in water attached to a piece 

 of wood. In about 24 hours I found the half Sagartia closed again and 

 after a few days the animal was perfectly restored, only counting a 

 smaller number of septa, but even these were in time partially replaced. 

 The specimen, however did not grow larger, although I fed it with 

 mosquitoes and various larva? for about six months. The other half 

 which was removed from its place of attachment died shortly afterwards. 



d. Habitat. 



It is generally stated that all the Actiniacea are truly marine 

 animals, and there are indeed very few instances known where 

 species have for a time been kept in aquaria in which the saline con- 

 stituents of the water were in proportion considerably less, than repre- 

 sented in pure sea-water. Actinice, and others, are sometimes found 

 attached to rocks above the low-water mark, or living in small pools 

 of sea-water, but I am not acquainted with any record of a species 

 having been observed living permanently in brackish water. 



The present species was found, as I have already stated, in one 

 of the tanks close to the railway station of Port Canning. It lives 

 here attached to old trunks of trees* I have not observed it in any of 

 the other tanks, partially on account of a difference in the water, 

 partially on account of the want of any fit places of attachment. The 

 specimens which I collected were of different size, the smallest about 

 one quarter of an inch in the basal diameter, and the largest measuring 

 about 1 J inches in the same diameter. They usually were seen 8 

 or 10 inches below the surface of the water but sometimes at the sur- 

 face itself ; sometimes even a part of the animal was above it, and 

 while the exposed portion became perfectly dried up under the direct . 

 influence of the sun, the other half remained as usually vital. 



Slight progressive movements have often been observed in Actinia 



* Hseckel's name Petracalephce would on this account not suit this species, "WO 

 had to create a name something like Lignacalephce. 



I, 



