TURRIS NEGLECTA. 13 



ground of this trifling difference. If the genus Merona 

 were adopted, we must dismember the very natural group 

 of forms now included under the genus Eudendrium. 



Hub. " Tubiclava cornucopias was dredged in from 80 to 

 100 fathoms, about 20 miles north of CJnst in Shetland, 

 and was parasitic on the shells of Astarte sulcata and Den- 

 talium entails. It is worthy of remark that in every 

 instance the Hydrozoon was observed upon shells still 

 occupied by the living Mollusca, and that it invariably had 

 assumed a position at the posterior extremity of the shell, 

 where it would receive the benefit of the aqueous currents 

 caused by the mollusk, which, while providing for its own 

 necessities, thus unwittingly performed the kindly office of 

 feeding its hungry neighbour " (Norman) : coast of Nor- 

 thumberland, "on the posterior end of a Dentalium en- 

 talis " ( J. A.) 



Genus TURRIS, Lesson. 



Der. Turris, a tower. 



GENERIC CHARACTER. Stems short, rooted by a filiform 

 stolon, bearing the polypites on their summits ; the ccenosarc 

 invested by a polypary ; polypites claviform, with scattered 

 filiform tentacles. 



Gonozooid free and medusiform. Umbrella subcylin- 

 drical, with 4 or 8 longitudinal bands ; manubrium massive, 

 four-lipped ; radiating canals 4 ; marginal tentacles nu- 

 merous, each with an ocellated bulbous base. 



T. NEGLECTA, Lesson. 



TURIUS N-EGLECTA (the free zooid), Lesson, Prodr. No. 38 ; Acal. Hist. 284 ; 

 Forbes, Brit. Naked-eyed Medusa 1 , 23, pi. iii. fig. 2 ; Gosse, Devonsh. 

 Coast, 348, pi. xiii. figs. 6-10 ; AHman, Ann. N. H. (3rd ser.) xiii. 

 3; r >2 (May 18fi4). 



