76 



ANTHOZOA. 



ments, which, however, communicate freely with each other and like- 

 wise with the interior of . 3g 

 the tentacula, as seen at 

 e. Every tentacle is per- ^ 

 forated at its extremity 

 by a minute aperture, b, 

 whereby the sea-water is 

 freely admitted into these 

 compartments, so as to 

 bathe the interior of the 

 body; and when, from 

 alarm, the animal con- 

 tracts itself, the water so 

 admitted is forcibly ex- 

 pelled in fine jets through 

 the holes by which it 

 entered. There can be no 

 doubt that the surround- 

 ing fluid, thus copiously 

 taken into the body, is 

 the medium by which 

 respiration is effected ; 

 and every one who has 

 been in the habit of keep- 

 ing Actiniae in glass-vessels for the purpose of watching their proceed- 

 ings must have noticed that, as the fluid in which they are confined 

 becomes less respirable, from the deficiency of air, the quantity imbibed 

 is enormous, stretching the animal until it rather resembles an inflated 

 bladder than its original shape. 



(169.) It is in the compartments thus (at the will of the creature) 

 distended with water that we find the organs of reproduction, which 

 here assume a development far exceeding what we have noticed in 

 other zoophytes. On raising a portion of the membrane forming the 

 stomach, as at /, we see lodged in each partition an immense number 

 of granular corpuscles attached to a delicate transparent membrane, and 

 arranged in large clusters, g. The ovigerous membrane that secretes 

 these corpuscles is represented unravelled at h ; it is through its whole 

 extent bathed with water admitted into the compartment wherein it 

 is lodged a circumstance which provides for the respiration of the em- 

 bryos during their development. 



(170.) We learn from the researches of MM. Kb'lliker and Erdl 

 that the Actiniae are bisexual, and that the male and female organs are 

 allotted to different individuals, the testes of the male and the ovaria 

 of the female being so similar in their structure and appearance that 

 the difference between them is only appreciable with the microscope. 



Section of Actinia. 



