ZOOPHYTA ASC'IDIOIDA. 241 



creting follicles, and distinct oral, cardiac, pyloric, and anal ori- 

 fices. The whole floats freely in a visceral cavity, the bound- 

 aries of which are formed by the delicate transparent parietes 

 of the animal ; the space between the alimentary canal and the 

 parietes being occupied by a clear fluid, and by the muscles 

 which act upon the animal."* 



Let us now suppose that the polypes are in a state of extru- 

 sion and fully expanded, as represented in Fig. 39, a ; all the cilia 

 in play, and the water whirling in rapid streams up and down 

 the opposite sides of the tentacula, carrying with them nutri- 

 ment and the breath of life. All is quietness and security 

 around, and the little creatures are evidently in a state of hap- 

 piness and enjoyment : no one who has witnessed the micro- 

 scope scene, — the myriads of the little flosculous heads that 

 pullulate and blossom over the entire polypidom, as thickly 

 peopled as the swarming hive, can have any doubt of this,-}- es- 

 pecially when he remarks the acuteness and vivacity of their 

 sensibilities and actions, for, under his eye, one will ever and 

 anon suddenly sink out of view, hide itself within the cell, again 

 on a sudden emerge and expand, or, it may be, lay itself down 

 in repose and concealment, until digestion has freed it from a 

 state of repletion, or forgetfulness has removed the alarm of an 

 enemy.:}: These positions are assumed with such a rapidity that 

 the eye cannot trace the steps of the process ; and large glasses 

 and minute skill are required to reveal to us its mechanism. 



• Farre in lib. cit. p. 393. 



t " The heart is hard in natm-e, 



that is not pleased 



With sight of animals enjoj'ing life, 

 Nor feels their happiness augment his own." 



Cowper- 

 \ " 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 deli- 

 cacy of their sense of touch very strongly marked, but the operations also con- 

 sequent 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 ex- 

 pose itself to water that has become in the least degree deteriorated." — Farre in 

 Phil. Trans, an. 1837, p. 414. 



