BIGELOW: MEDUSAE AND SIPHONOPHOR AE. 407 



VOGTIA GLABRA, sp. nov. 



Plate 4, fig. 2-7. 



Station 10,202, 450-0 meters, one specimen with 3 nectophores; 

 also 4 loose nectophores; in good condition. Type. 



In its general organization, this new species agrees exactly with 

 other species of Vogtia (1911b, 1913), and with Hippopodius hippopus, 

 particularly in the relationship of the elongated " knospungzone " 

 which bears the nectophores to the siphosome, of which Chun (1897a, 

 1913) and Richter (1907) have given excellent accounts. But the 

 nectophores are strikingly characteristic. The youngest nectophore 

 (aside from a very small bud), already 7 mm. long, is elongate in out- 

 line (Plate 4, fig. 2, 3), its apex prolonged into a triangular process, 

 and there are two principal dorsal prominences, one on either side, 

 about mid-way between the nectosac and the apex, which, though 

 trivial in their nature, prove to be an important specific character. 



In ventral view (Plate 4, fig. 3), it is seen that there is a deep hy- 

 droecial groove, running the whole length of the nectophore, and 

 partially enclosed by its lateral flaps, particularly near the apex. 

 At this early stage the ventral sinus is large. 



The next older nectophore (Plate 4, fig. 4) already 17 mm. long, is 

 relatively shorter and broader, and its outline more rounded. But 

 the apical point, and the two dorsolateral prominences are as evident 

 as at the earlier stage. And there is no trace of the four dorsal promi- 

 nences which bound the margin of the nectosac in //. hippopus, 

 unless the dorsolateral p.'ominences can be said to represent them. 

 Corresponding to the general alteration in the shape of the nectophore, 

 which takes place with growth, the hydroecial groove is shallower, 

 and broader, its enclosing flaps lower; and the ventral sinus has de- 

 creased in relative size. 



The large nectophores (27-30 mm. broad) are nearly circular in 

 outline (Plate 4, fig. 5), with very broad, shallow hydroecium. But the 

 two dorsolateral, and the apical, prominences are as evident as before. 



The rounded outlines of the nectophore separate V. glabra at a 

 glance from the other members of Vogtia. And though it resembles 

 Hippopodius hippopus superficially in this respect, the bells of the two 

 species differ characteristically in detail. Thus, in the latter, the 

 apex of the bell is rounded, not pointed, even in nectophores only 3-4 

 mm. long, while the dorsolateral prominences of Vogtia glabra are 



