LIZZIA. 



161 



LIZZIA Forbes. 



Lizzia Forbes. Brit. Naked-eyed Medusse, p. 64. 1848. 

 Lizzia Agass. Cont. Nat. Hist. U. S., IV. p. ,^45. 1862. 

 CytCEis Sars (non Esch.). Beski-iv., p. 28. 1835. 



Lizzia grata A. Agass. 



Lizzia grata A. Agass. ; in Proc. Bost. Soo. Nat. Hist., p. 100, Figs. 28, 29. 1862. 



The presence of a cluster of tentacles, intermediate between the 

 chymiferous tubes gives to Lizzia a totally different aspect from that 

 of Bougainvillia, which is the permanent embryonic type of Lizzia. 

 In a young Lizzia this middle cluster is wanting ; the character of the 

 development of the tentacles is totally different from that of Bougain- 

 villia ; we have an odd tentacle at first (Fig. 252), and then pairs of 



tentacles (Fig. '253), while in the Bougainvillia we have, for the first 

 set, as well as for the subsequent cycles, a pair of tentacles ; so that we 

 may have, as members of the same family, forms in which these clus- 

 ters are reduced to a minimum, as in Dysmorphosa (Fig. 259), where 

 the odd tentacle alone is developed. 



In an adult Lizzia (Fig. 251) the chymiferous cluster of tentacles 

 consists of five, the intermediate cluster of three. The order of succes- 

 sion of the different tentacles in the young stages can easily be traced 

 in Fig. 252 ; at first there are four long tentacles opposite the chymif- 

 erous tubes, flanked by two short tentacles ; next the odd tentacle of 

 the middle cluster makes its appearance, and then after some time the 

 other pair of tentacles of the middle cluster. The sensitive bulb of the 

 adult is elongated, polygonal, and thickly covered with pigmentrcells 

 (p, Fig. 253) ; the digestive cavity of the adult (Fig. 254) is nearly as 

 long as the cavity of the bell, mto which a short projection of the bell 



Fig. 251. Adult male Lizzia grata, seen in profile ; magnified. 



Fig. 252. Quarter of the disk of a young Lizzia. 



Fig. 253. Magnified view of the sensitive bulb, p, pigment-cells. 

 NO. II. 21 



