POLYZOA INFUNDIBULATA. 259 



which is armless, having in no instance either jaws or teeth. 

 It is the entrance into a long membranous gullet (i), of perfect 

 transparency, and which can be traced through its equally 

 transparent envelope, to its termination in a somewhat globular 

 and comparatively large organ placed near the curvature of the 

 body, and rendered opaque partly by the greater thickness and 

 fleshiness of its structure, but perhaps more so by the nature 

 of its contents. This is the stomach (c), and from the side of 

 it there proceeds a narrow intestine (<#), which follows a 

 straight upward course along the side of the gullet, and opens 

 at the aperture of the cell by a separate orifice, from which 

 the undigested remains of the food are ejected. There is 

 another organ of a roundish figure appended to the bend of 

 the intestine, which is supposed by some to be an ova- 

 rium (0),* but it seems not unnecessary to remark, that this 

 appropriation of it to the generative function has perhaps 

 no better proof than what is derived from a similarity of 

 position between it and the supposed ovarium of the com- 

 pound mollusca. It is, I presume, the organ which Blainville 

 says he is willing to believe performs the functions of the 

 liver.f 



No trace of a nervous J or vascular system of any kind has 

 been detected, nor is there any organ of sense, but the polypes 

 are notwithstanding very sensible of external impressions. 

 When left undisturbed in a glass of fresh sea-water, they 

 push their tentacula beyond the mouth of the cell by straight- 

 ening the body ; and then expanding them in the form of a 



* Thompson, Zool. Researches, p. 96. 



t Manuel d'Actinologie, p. 72. According to Van Beneden, there is no trace of 

 liver in these polypes. Rech. sur les Laguncula, &c. p. 8. 



J " No trace of either nerves or ganglia could be detected ; yet the attributes of a 

 nervous system were so clearly exhibited as to leave no doubt but that this must 

 exist, and probably in some degree of perfection. Not only was the delicacy of 

 their sense of touch very strongly marked, but the operations also consequent upon 

 the enjoyment of such a sense were sometimes singularly striking. This is seen in 

 the instant retiring of the animal on the slightest alarm, and the caution which it 

 sometimes shows before emerging again from its cell ; in the obvious selection of its 

 food ; and in the pertinacity with which it refuses to expose itself to water that has 

 become in the least degree deteriorated." Farre in Phil. Trans, an. 1837, p. 414. 

 Traces of a supra-oesophageal ganglion and nerves, similar to the more defined system 

 of the Mollusca tunicata, have been since observed by Van Beneden. Rech. Les 

 Laguncula, p. 1 1 . 



s 2 



