166 



ZOOLOGY 



SECT. 



Lucernaria (Fig. 118), a genus not uncommon on the British coasts, is in one 

 respect even more like a Scyphula, since it is attached by a peduncle developed 

 from the centre of the ex-umbrella. The margin of the umbrella is prolonged 

 into eight short hollow adradial arms, bearing at their ends groups of short 

 adhesive tentacles (t.). As in the Scyphula, each gastric ridge contains an 



FIG. 118. XiUCeraaria. A, oral aspect ; B, from the side ; g. foot-gland ; (/. /. gastric filaments 

 gon. gonad ; mth. mouth ; t. tentacles ; tn. tsenioles. (After Glaus.) 



infundibulum, lined with ectoderm and opening on the sub-umbrella. The 

 gastric filaments (g. f. ) are very numerous a distinct advance on Tessera and 

 the gonads (gon. ) are band -like. There are no sense-organs in Lucernaria, but 

 in an allied genus degenerate tentaculocysts are present. 



ORDER 2. PEROMEDUS.E. 



This group includes a small number of rare and beautiful Medusae of curiously 

 complex structure, of which Pericolpa may be taken as an example.- The umbrella 

 (Fig. 119) is always conical, and is divided by a horizontal furrow into an apical 

 region or cone (en.) and a marginal region or crown; the crown is again divided 

 by a second, rather irregular horizontal furrow into a series of pedal lobes (pd. I. ), 

 adjacent to the cone, and a series of marginal lappets (mg. Ip. ), forming the free 

 edge of the bell. x , 



Four of the pedal lobes, inter-radial in position, bear tentaculocysts (tc.), four 

 others, per-radially situated, give origin to long, hollow tentacles (t. ). In the 

 more complex genera there are eight additional adradial tentacles. 



The mouth (mth. ) is very large, and leads by a wide manubrium (mnb. ) into a 

 spacious stomach (st. ), which is continued (yiite to the apex of the cone. In the 

 wall of the stomach are four wide "p'er-radial slits, leading into an immense 

 circular sinus (circ. #.). As in Lucernaria, there are four wide inter-radial in- 

 fundibula. The gastric filaments (g. f. ) are very numerous, and the elongated 

 U-shaped gonads (gon.) are eight in number and adradial. 



ORDER 3. CUBOMEDUS/E. 



The Jelly-fishes forming this order are, as the name implies, of a more or less 

 cubical form, resembling a deep bell with somewhat flattened top and square 

 transverse section. They resemble the hydrozoan Medusse more than any of the 

 other Scyphozoa. The best known species, Charybdcea marsupialits (Fig. 120), is 

 about 5 cm. in diameter and of very firm consistency. 



