LTJCERNAEIA. 47 



touch is, however, sufficient to make it close upon itself, shrink- 

 ing together in the attitude of the third individual in Fig. 54, or 

 even drawing its tentacles completely in, and contracting all its 

 parts till it looks like a little ball hanging on the stem. These 

 are but a few of its manifold changes, for it may be seen in every 

 phase of expansion and contraction. Let us now look for a mo- 

 ment at the details of its structure. The resemblance to a cup or 

 vase, as in the upper figure of the wood-cut (Fig. 54), is decep- 

 tive ; for a vase is hollow, whereas the Lucernaria, though so deh- 

 cate and transparent that its upper surface, when thus stretched, 

 seems like a mere film, is nevertheless a solid gelatinous mass, 

 traversed by certain channels, cavities, and partitions, but other- 

 wise continuous throughout. The peduncle by which it is at- 

 tached is but an extension of the floor of a gelatinous disk, cor- 

 responding to that of any JeUy-fish. Four tubes pass through the 

 whole length of this peduncle, and open into four chambers, 

 dividing the digestive cavity above into as many equal spaces. 

 (Fig. 65.) These spaces are jj^ ^^ 



produced by folds in the up- 

 per floor of the disk, uniting 

 it to the lower floor at giv- 

 en distances, and forming so 

 many partition-walls, dividing 

 the digestive sac into four dis- 

 tinct cavities. These lines of 

 juncture between the two 

 floors, where the partitions oc- 

 cur, produce the four radiat- 

 ing lines, running from the 

 proboscis to the margin of the 

 disk, on the upper surface. (Fig. 55.) The triangular figures, 

 running from the mouth to each cluster of tentacles, are pro- 

 duced by the ovaries, which consist of distinct pouches or bags 

 attached to the upper surface of the disk, and hanging down into 

 the cavities below ; every little dot withia these triangular spaces 

 represents such a bag. Each bag is crowded with eggs, which 

 drop into the digestive cavity at the spawning season, and are 



Fig. 55. Lucernaria seen from the mouth side 



