152 PEOF. ALLMAK ON NEW HTDEOIDA FROM 



pliore; intrathecal ridge strongly marked, running round the 

 hydrotheca at the junction of its lower and middle third ; lateral 

 nematophores not overtopping the hydrotheca ; mesial nemato- 

 phore adnate to somewliat less than the lower third of the hydro- 

 theca, then meeting the keel and. ending as a short free process. 



Gonosome not known. 



Locality. Gulf of Mexico. 



The present very minute species, which scarcely exceeds a 

 fourth of an inch iu height, was found creeping over gulf-weed. 

 Its strong intrathecal ridge gives to the hydrotheca a decidedly 

 bithalamic character, indicated even externally by a slight con- 

 striction at the level of the ridge. The two spine-like processes 

 which lie at the distal end of every pinna are probably modified 

 nematophores. It is nearly allied to the equally minute Agla- 

 oplienia perpusilla of the United-States Exploration of the Grulf- 

 Stream. It differs, however, from .^.^erpas^Z^a by the greater 

 width of the keel, and by the greater depth of the hydrotheca, 

 and the more strongly marked intrathecal ridge. No gonosome 

 was present in either species. 



I have obtained Aglaoplienia late-carinata from other collections 

 of gulf-weed. It appears indeed to be quite a characteristic 

 form of the hydroid fauna of the floating Sargasso field of the 

 North Atlantic. 



Aglaophenia DOLTcnocAEPA, n. sp. (PL XXIY. figs, 1-4.) 



Tropliosome. — Stem simple ox very sparingly branched, mono- 

 siphonic ; hydrocladia alternate, closely set, and with short inter- 

 nodes. Hydrothecas conical, with the margin slightly everted and 

 having four teeth on each side, and one mesial tooth in front ; 

 the anterior of the four lateral teeth is strong and furcate, the 

 posterior long and pointed, and the intermediate two teeth short 

 and blunt ; intrathecal ridge strong, situated near to the fundus 

 of the hydrotheca ; mesiaSl nematophore adnate to the hydrotheca- 

 walls for the entire height of the walls, and with its free terminal 

 portion short and truncate ; lateral nematophores wide, scarcely 

 overtopping the hydrotheca. 



Gonosome. — Corbula completely closed, very long, cylindrical, 

 composed of about twenty costae. 



Locality. Australia, 



The most characteristic feature of this beautiful species, which 

 attains a height of about 6 inches, will be found in the very 



