68 ZOOPHYTES. 



Thus, if these hydrre shall be considered nascent animals, as is pro- 

 bable, their genus can be ascertained only from the mature or adult speci- 

 men, on the ultimate form and appearance of which it would be vain to 

 speculate. 



Plate XIX. Fig. 7. Triticella flam. 



§ 7. Crisia eburnea. — Tufted Ivory Coralline. — Plate XIX. 

 Figs. 8-13. — So many different elements are combined in this zoophyte, 

 as to render its precise place in the Systema questionable, until determined 

 by the additional light which may be thrown on its nature. But it is 

 one of the smaller and more delicate species, and its aspect is so well de- 

 fined, as to preclude any mistake in regard to identity. 



The tufted ivory coralline rises nine lines or little more in height, 

 and diverges as much across, by subdividing boughs and branches, all the 

 parts incurving over its short stem. A double row of cells in semi-alternate 

 arrangement, and considerably apart from each other, clothes the inside 

 of the branches. Owing to the effect of this disposal, the exterior of the 

 specimen is of irregular convexity. The subordinate parts are articulated ; 

 each articulation comprehending several cells. The whole is of the purest 

 white, and of shelly consistence, brittle to the touch. — Plate XIX. figs. 8, 9. 

 A portion enlarged, fig. 10. 



An ascidian hydra, with eight tentacula, inhabits the cell, which has 

 a low projecting lip ; and as all project inwards, they are difficult to be 

 seen, unless the subject be reduced to fragments. A very minute portion, 

 thus obtained, is magnified, fig. 11, and the bydrse, figs. 12, 13. The ten- 

 tacula issue forth as a pencil ; they recurve slightly when unfolded : they 

 are of slender proportions, and exercise the percussive faculty of their kind. 

 The higher extremity of the body scarcely protrudes beyond the orifice 

 of the cell. In as far as the rest can be observed, the whole animal is 

 small and pellucid, or of the faintest grey. A dark reddish internal ob- 

 ject is visible, far down the cells, as in other species. 



Ovular bodies, of considerable size, with an orifice in the summit, are 



