COMPOSITION AND STRUCTURE. 29 



network of cells for the retention of the fluid part of its substance. 

 Constituted in this manner, the Jelly-fish are of the most fragile 

 and evanescent character. No sooner are they removed from the 

 water, and no matter how carefully, than their delicate tissues be- 

 come ruptured, and the contained fluid drains away, so that at 

 the expiration of a few hours, of the whole bulky mass of trem- 

 bling jelly, nothing remains but a thin pellicle of film, scarcely to 

 be distinguished from an ordinary cobweb. It is a common 

 amusement with boys on some parts of the southern coast, where 

 these creatures are generally known as " water-blobs," to catch 

 the smaller varieties, and hold them in the hand, while they 

 thus gradually melt, as it seems, away. Dr. Carpenter states 

 that large specimens, weighing, when first taken from the water, 

 from fifty to sixty pounds, are reduced to a thin coating of filmy 

 web, weighing scarcely as many grains. And what adds to the 

 wonder is, that the fluid which escapes is in no way to be dis- 

 tinguished, even when submitted to chemical analysis, from 

 ordinary sea-water. 



Mr. Patterson, in his " Introduction to Zoology," relates an 

 amusing case of a farmer, who had been in the habit of employing 

 his men and horses in carting away from the sea-shore large 

 quantities of Jelly-fish for the purpose of manuring his fields, and 

 who, happening one day to hear a lecture in which the structure 

 of these animals was explained, was not a little astonished to find, 

 that in every ton of " sea-blubber," which he had been taking so 

 much trouble to obtain, the entire amount of solid matter was 

 scarcely more than he could carry home in one _f his coat-pockets. 

 In none of these animals, so far as is yet known, is there any- 

 thing like a distinct nervous system. Some few investigators 

 have imagined that they could detect the presence of nervous 

 threads or filaments, but the suspicion has never been verified, 

 and the physiologist still ranks the Jelly-fish with the animals 

 whose nervous matter, if they have any, is indistinct and beyond 

 our powers of discovery. Respiration, too, is carried on by means 

 equally obscure ; the probability being, that all the air required 

 for the purpose is separated from the sea-water as it freely passes 

 through the channels of the body. In some species there are 

 some small red spots around the margin of the body, which 

 are regarded as rudimentary eyes, although it is by no means 

 certain that they are endowed with the power of vision. It is 



