162 



LIZZIA GRATA. 



extends ; the genital pouches are on the sides of the digestive cavity, 

 extending neai-ly to its extremity. The actinostome terminates in four 

 large lobes, edged with short oral tentacles, surmounted by a knob of 



lasso-cells ; these lips are quite expansive and contractile, (t, f, t", t'", 

 Fig. 255.) In the young Medusse the digestive cavity terminates with 

 only four club-shaped tentacles {t, Fig. 256) ; this soon branches in 



Pig. 258. 





somewhat older stages, as that of Fig. 252, and assumes the shape of 

 Figs. 257, 258, t, additional club-shaped oral tentacles being added in 

 the order in which they are numbered in Fig. 255. 



Massachusetts Bay (A. Agassiz). 



Cat. No. 446, Nahant, A. Agassiz. Medusa. 



Fig. 254. Proboscis of male Lizzia ; magnified. 



Fig. 255. One of the four lobes of the actinostome, seen from above, t, t, 1', t", t'", tentacles 

 of actinostome. 



Fig. 256. Actinal view of the proboscis of a young Lizzia. t, oral tentacle ; d, digestive cavity. 



Fig. 25 7. Actinal view of proboscis of an older specimen, a, actinostome ; g, genital pouches ; 

 t, tentacles of actinostome. 



Fig. 258. Abactinal view of Fig. 257, somewhat less magnified, with the oral tentacles in a 

 difierent attitude : lettering as above. 



