94 LECTURE VIII. 



like little trees adorned with polypetalous flowers and supporting 

 their annual crop of deciduous fruit or seed-capsules, deceived such 

 clear-sighted observers as Tournefort and Ray as to their real nature, 

 and were classed by them with vegetables ; if organised beings, so 

 obviously like plants in external form and in some of their most con- 

 spicuous changes, can be proved by the anatomist to belong un- 

 equivocably to the Animal Kingdom, without the determination 

 being vitiated or obscured by any real or essential vegetable charac- 

 ter: — if the calcareous masses of Madrepores and Millepores, classed 

 by Boccone and Guison as species of minerals, and which once were 

 the subjects of curious speculations on the growth of stones, have 

 been proved by the recognition of the more complicated organisation 

 of the polypes which they support, to be the products of the 

 vital actions of such polypes, and as essentially a part of those 

 animals as the skeleton of a man is a part of his body — still more 

 does the anatomical structure of the third division of polypes prove 

 how inadequate is a superficial survey of an organised being to lead 

 to true notions of its nature and affinities. The Bryozoa, which 

 coat, as with a delicate moss, fuci, shells, or other marine productions, 

 or which rise in dendritic forms, like the hydrozoic corallines, 

 with which they have been confounded by Ellis, with which they 

 would equally have passed for plants with Ray, are, perhaps, the 

 most striking examples of how comjDlicated an animal structure may 

 be masked by mere outward form. 



An animal differs from a plant in having a stomach and a mouth, 

 it is thereby qualified to exert its most conspicuous animal property, 

 that of locomotion. 



A locomotive organised being must possess an internal digestive 

 store-room ; but the converse of the proposition does not hold good, 

 — a digestive cavity does not imply the powers of locomotion. 



The Bryozoon has not merely the characteristic digestive cavity, 

 like the Hydra and the Actinia : it has not merely a mouth and pre- 

 hensile organs for the capture of living prey ; but it has also an 

 oesophagus for deglutition, an intestine for the separation of the nu- 

 trient chyle, and a distinct external outlet for the indigestible refuse 

 of the food : it may possess a stomach w ith strong muscular walls and 

 a dentated lining for trituration, and a second stomach wdth glandular 

 walls for digestive solution or chymification, and thus present an ali- 

 mentary canal as complicated and as highly elaborated as in the bird. 

 Yet the microscopic polypes which manifest this high condition of the 

 digestive apparatus are fettered to the spot, w^here, as ciliated gem- 

 mules, they finally rested after their brief early locomotive stage : the 



