VOGTIA SPINOSA. 211 



300 fathoms to surface 1 specimen with 4 nectophores and 



6 detached nectophores. 

 surface 1 specimen with 6 definitive nectophores. 



loose nectophores. 

 300 fathoms to surface. 

 " " " "1 specimen with 10 nectophores, and 



7 detached nectophores. 

 " " " " 1 specimen with 13 nectophores. 

 " " " " 1 specimen with 11 nectophores. 

 " " " " 3 large detached nectophores, in poor 



condition. 



The arrangement of tlie nectophores follows exactly the same plan as it 

 does in the better known genus Hippopodius. As in that genus the nectosome 

 is composed of two series of obliquely placed alternating nectophores, the oldest 

 at the bottom. Their concave ventral surfaces form a typical hydroecial canal, 

 within which the stem with its appendages is entirely retracted in all the speci- 

 mens studied (Plate 15, fig. 5). 



Observations on the living colonies showed that the nectosome is no more 

 effective as a swimming organ in Vogtia than it is in Hippopodius. Indeed the 

 arrangement of the nectophores precludes the possibility of any but the oldest 

 two so serving. In all the others the opening of the nectosac is closed by the 

 anterior surface of the neighboring nectophore. As in Hippopodius the necto- 

 phores are attached to a zigzag muscle band, which, as Chun has shown ('97a), 

 is nothing more than the very much prolonged "Knospungszone." So close 

 is the resemblance in this particular between the two genera that except for 

 the form of the nectophores Chun's figure ('97a, fig. 11) of a longitudinal section 

 of the siphosome of Hippopodius might equally well apply to Vogtia. 



Nectophores. The older nectophores, as shown by Haeckel ('88b, pi. 29, 

 fig. 12) may be likened in their outlines to short pentagonal prisms (Plate 15, 

 fig. 9). The largest are about 20 mm. broad. The arrangement of the char- 

 acteristic gelatinous tubercles or spines can be better shown in the figure than 

 in the description; but I may call attention to the fact that they occur closely 

 crowded not only on the margins of the facets, but on the lateral and dorsal 

 facets themselves. In V. penlagona, so far as we yet know, they are entirely 

 restricted to the angles. The ventral facet, which is deeply concave, is without 

 spines. The youngest nectophore in one colony, 3 mm. broad, is more nearly 

 rectangular, when seen from the basal side, and it has spines only on the dorsal 



