COMPARATIVE ANATOMY. 



145 



COMPARATIVE ANATOMY. IV. 



COCLENTEKATA : 1IYUKOZOA. 



TUB animals placed under this sub-kingdom exhibit tlioir ., 

 rank, not only in the distinctive character of possessing mem- 

 branes of definite structure, composed of or containing colls, 

 wo have already remarked cuts them off from tho Pro- 



TV. 



our field* and adorn oar gardens. Wo may talc* as a typical 

 representative of these animals, a genus called Cntnpnmilana. 



Tho very name is similar to that given to a 

 flower, the Campanula; and it is given to it for th* same 

 reason. Both have at tho ends of their branches cup-shaped 

 organ*, very much like bolls. It is true that, in the Mim*!, the 

 hell, instead of hanging as a boll should, has iU mouth upward : 



I., II. EUDENDRIUN RAMOSUM (HTDROZOON). III. HlDROZOON ENCRUSTING A SHELL (NATURAL SIZE). IV. RHOPALONEHA VlLATUX, TBX Yl 



CLUB-TENTACLED MEDUSA A FREE SWIMMING MEDUSA. V. PERPENDICULAR SECTION OF A SKA ANEMONE. VI. TRANSVERSE SECTIOI o 

 A SEA ANEMONE. VII. PLEUROBRACHIA, A CTENOPBORE BELONGING TO IHE ACTINOZOA. VIII. TRANSVERSE SECTION or PLKUBOBKACVU 

 (CTENOPHOJIE). 



Eefs. to Noa. in Figs. (I.) 1, feeding organs, with fringe of tentacle*, month, and stomach (thaded) ; 2. flower-like organ* of reprodnctioi 

 which become detached and swim away, as in Fig. II.; 3, creeping stem. (IV.) 1, polyp suspended within (2) the wimminff-cap ; 3, 

 its veil. (V.) 1, organs of reproduction on the edge of a septum ; 2, the face of a septum. (VI.) 1, the stomach wall ; 3, the body wmll ; 

 3. septa joining the walls. (VII., VIII.) 1, mouth ; 2, centre of the stomach ; 3, comb-like locomotive organ*; 4, sack into which thr 

 tentacles can be withdrawn ; 5, tentacles cut short ; 6, nerve-knot and organ of sense. 





tozoa, but also from the fact, that in this class wo find the first 

 indications of many of the structures which are necessary to, 

 and acquire such a great development in, tho animals higher than 

 themselves. Definite membranes, muscular fibre, nervous and 

 hepatic (liver) tissues are found in some of these animals. 



A glance at any of the more common forms, such as arc 

 represented in Figs. I., II., III., will at onco suggest that 

 these animals have a mode of prowth and a general form very 

 similar to the higher forms of vegetables, such as grow in 



36 -X.E. 



but in another respect the resemblance is better maintained, for 

 in the centre of the bell there rises a thick club-shaped body. 

 which may w.-ll represent the clapper. The resemblance to a 

 plant is maintained throughout the whole of the external form 

 of thi animal. With a creeping network of roots (if we may 

 so call them), it encrusts some submarine rock, or stone, or shelL 

 From this it sends up branching stems, each branch of which is 

 terminated either with a flower-like cup, which protects a tubular 

 body with a mouth at its far end, surrounded with, a circlet of 



