362 EVENINGS AT THE MICROSCOPE 



disturb the water with it. Ha ! what a circle of tiny lamps 

 flashes out! You struck the body of the Thaumantias 

 with the pencil, and instantly, under the stimulus of 

 alarm, every purple eye became a phosphoric flame. 

 Touch it again; again the crown of light flashes out, but 

 less brilliantly; and each tiny lamp, after sparkling trem- 

 ulously for a moment, wanes, and the whole gradually, 

 but quickly, go out, and all is dark again. 



But it is tired of lighting up .for nothing or its' gas is 

 exhausted or it is become used to the pencil and is not 

 alarmed or, at all events, you may knock it, and push it, 

 but it refuses to shine any more. Back with it then to 

 the microscope, and let us see if it possesses any other 

 points of interest for us there. 



Yes: we have not exhausted the organs of the margin 

 yet. Between the tentacles which spring from bulbs there 

 are a good many more, far more minute, without any 

 bulbs from four to seven between every two of the pri- 

 mary ones. We won't mind these, but bringing the mar- 

 gin itself into focus, and moving it along the stage hori- 

 zontally, we presently see one and another singular organs. 

 They are eight in all, two being placed, but irregularly, 

 in each of the four quadratures of the circle formed by 

 the radiating canals. 



There are auditory vesicles, or organs of hearing, very 

 closely similar to those which we see imbedded in the 

 bosom of the Snail and other Mollusca. Here they are 

 comparatively large, and unusually well furnished. Each 

 is a semioval enlargement of the flesh of the margin, in 

 close connection with the walls of the marginal canal, hol- 

 lowed so as to enclose a capacious cavity, in which are 

 placed a considerable number from thirty to ffty in this 





