476 PEOFESSOE G. J. ALLMAN ON THE HYDEOIDA 



Gonosome. — Corbula closed, rather elongated, ^vith seven or eight moderately deve- 

 loped serrated ribs ; no free spur-like appendage at its base. 



Aglaophenia dromaius is a lax flexile species, strongly suggesting, both in size and 

 form, one of the slender loose-barbed plumes of an Emu's feather. It comes very near 

 to Aglaophenia tuhuUfera., Hincks, from which, however, it differs by its smaller lateral 

 nematophores, and by its more elongated corbulae as well as by the slighter development 

 of their serrated crests, and by the absence of the spur-like appendage at their base. 

 It was dredged off the Spanish coast from a depth of 539 fathoms. 



Aglaophenia elongata. Plate LXVII. figs. 2, 2", 2*. 



Trophosome. — Stem attaining a height of about six inches, irregularly or subalter- 

 nately branched, not fascicled, divided into equal internodes ; pinnae slender, alternate, 

 each attached to a point a little below the distal end of an internode. Hydrothecae 

 deep and narrow, nearly cylindrical, margin cut into distinct and equal teeth ; intrathecal 

 ridge extending but a short distance from the posterior walls of the hydrotheca near the 

 fundus of its cavity ; mesial nematophore adnate for nearly its entire length, and attaining 

 about one third the height of the hydrotheca ; lateral nematophores scarcely overtopping 

 the hydrotheca. 



Gonosome. — Corbulae closed, short and deep, with about seven moderately developed 

 serrated ribs. 



This is a slender,loosely branched, rather straggling form, and is especially distinguished 

 by its deep narrow hydrothecae. It was dredged along with Aglaophenia dromaius on 

 the coast of Spain from a depth of 539 fathoms. 



Halicornakia, Busk (modified). 



Trophosome. — Hydrocaulus with pinnate ramification. Hydrothecae usually with an 

 intrathecal ridge. Nematophores fixed ; lateral nematophores one on each side of the 

 orifice of the hydrotheca: mesial nematophores usually adnate for a greater or less 

 extent to the front of the hydrotheca, rarely free. 



Gonosome. — Gonangia not included in corbulae or protected by gonangial branches. 



f^ S The generic name Halicornaria was proposed by Busk for such Plumularidae as are 



, ' " deprived of corbulae, and are otherwise referable to the type of the Plumularia setacea of 



authors. The name of Halicornaria, however, is displaced by Lamouroux's prior name 

 of Aglaophenia, which, though applied by Lamouroux not only to the forms referable 

 to the type of Plumularia setacea but to those also which have Plumularia pluma of 

 authors as their type, may be now restricted to the latter, thus allowing the Plumu- 

 laria setacea and its allies to retain undisturbed possession of the name of Plumularia 

 assigned to both forms by Lamarck. Bather than introduce a new name, I have deemed 



