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be described. The ultimate mode or even point of termination of 

 these canals I was unable to make out satisfactorily. It seemed, 

 however, that the current of fluid in the canal did not penetrate far 

 into the base of the peduncle, but stopped at the point where the canal 

 became contracted, and was there turned back. The peduncle, for 

 convenience of description, may be divided into three portions ; an 

 upper portion or base, a central portion, and a lower portion consti- 

 tuting the mouth or lips. The upper portion or base (d, fig. 1) is the 

 most expanded ; it is colourless and transparent, and is composed of 

 a beautiful, very distinct cellular tissue (using the term not in a sense 

 very commonly understood of it as applied to the areolar tissue of 

 animals, but to designate a tissue composed of distinct polygonal 

 cells like those of certain vegetable tissues), as shown in fig. 1, and 

 fig. 10. The cells constituting the greater part and the interior of this 

 mass, are of irregular size and polygonal form, but towards the exte- 

 rior, as in the tentacular bulbs, the cells composing the tissue assume 

 more of a prismatic form, and thus constitute as it were a thick ex- 

 ternal layer, in some degree distinct from the rest of the mass. The 

 subumbrella or its lining membrane appears to be reflected on the 

 base of the peduncle, and to be lost or rather merged in its outer co- 

 vering. The cellular base of the peduncle is penetrated, to a certain 

 extent at least, as above described, by the four gastro -vascular canals, 

 immediately contiguous to which, the cells of the cellular tissue are con- 

 tracted and crowded. The cells of the cellular tissue are filled with a 

 transparent colourless fluid, which is rapidly dissipated by exosmosis 

 when the specimen is placed in a saline solution of greater density 

 than sea water, or in spirit, and in this condition the cellular base of 

 the peduncle, and together with it great part of the thickness of the 

 umbrella, disappears, and the specimen assumes something of the ap- 

 pearance shown in fig. 2. The middle portion of the peduncle is of 

 a quadrangular form and of a deep red or crimson colour : it con- 

 sists of the thick walls of the stomach or digestive cavity, and on the 

 four sides are placed the ovaries or reproductive glands. The walls 

 of the stomach are thick and dense, composed of elongated closely 

 packed prismatic cells, amongst which, and also on the external sur- 

 face of the peduncle, are numerous granular corpuscles, fig. 11. The 

 four angles are rounded and exhibit a rather laxer tissue, continuous 

 above with that of the basal portion, and below with the four angular 

 folds of the lips. The third or lowest portion of the peduncle is con- 

 stituted of four fimbriated and scalloped crescentic folds ; the sulci 

 between which correspond to the four sides of the peduncle, and 



