il8 EYENESTGS AT THE MICROSCOPE. 



cnidiJB, the ends of which project side bj side, as close 

 as tlie}'- can bo packed one against another. 



But still larger examples may be obtained from tlie 

 craspeda. "With a smart sudden blow I break the stony 

 skeleton of the Madrepore in sunder — the flesh tearing 

 apart also ; and thus I expose the interior of the living 

 animal. A great number of pellucid ribbons are now 

 seen, very much convoluted, which are named cras- 

 fcda. These are almost composed of large cnidcB. 



I remove with fine pliers a small fragment of one 

 of these ribbons, and placing it between the plates of 

 the compressorium, flatten it gradually till the plates 

 are brought into as close contact as they can be. A 

 high power now being put on, examine the organ in 

 question. 



You see a multitude of perfectly transparent, 

 colourless vesicles, of a lengthened ovate figure, con- 

 siderably larger at one end than at the other ; one of 

 average dimensions measures in length -^lo^h. of an 

 inch, and in greatest diameter -J--th. "In the larger 

 (the anterior) moiety, passing longitudinally through 

 its centre, is seen a slender chamber, fusiform or 

 lozenge-form, about esVoth of an inch in its greatest 

 transverse diameter, and tapering to a point at each 

 extremity. The anterior point merges into the walls 

 of the cnidcB at its extremity, while the posterior end, 

 after having become attenuated like the anterior, 

 dilates with a funnel-shaped mouth, in which the eye 

 can clearly see a double infolding of the chamber- 

 wall. After this double fold the structure proceeds as 

 a very slender cord, which passing back towards the 

 anterior end of the capsule, winds loosely round and 

 round the chamber, with some regularity at first, but 



