240 DIPHYOPSIINAE. 



Opposite them is a single narrow dorsal tooth, flanked on either side by a much 

 broader triangular tooth (Plate 6, fig. 6, To. L) ; and between each of the latter 

 and the corresponding ventral flap is a second triangular tooth or wing. The 

 latter vary greatly in apparent size with the condition of the specimens under 

 examination. In contracted material, as the result of the incurving of the bell- 

 margin, they are apparently very large. And it is thus that they were described 

 for the "Siboga" specimens; but in expanded examples, it is evident that much 

 of their bulk in reality belongs to the margin, not to the teeth (Plate 6, fig. 8). 

 They are not such definite structures as the other basal prolongations. The 

 ventral flaps, as seen in good specimens, are much the largest, and each bears 

 a minor tooth on its dorsal surface. 



The small size of the somatocyst has proved a constant character for the 

 entire series, and of itself would be sufficient to separate G. monoica from any 

 other member of the genus except the somewhat problematical G. turgida 

 Gegenbaur. 



Even when the margin is entirely destroyed anterior nectophores of monoica 

 can be distinguished from those of australis, which they nearly resemble in form, 

 by the course of the canals. ^Vhile in the latter the lateral canals arise from 

 the ring canal as usual (Plate 6, fig. 3), in monoica they arise from the ventral 

 vessel just above its union with the circular vessel (Plate 6, fig. 5). 



Posterior nectophores. The posterior nectophore of this species has not been 

 described. Its basal teeth are complex, there being a single undivided median 

 wing, bearing on its dorsal surface two secondary spines (Plate 6, fig. 7, X.), 

 and an odd dorsal tooth, flanked on each side by a triangular lateral one as in 

 the anterior nectophore. Of the last two, the dorsal is the larger. As is shown 

 in the key (p. 2313) the structure of the base separates it from the corresponding 

 nectophore of any other Galeolaria. The lateral canals are looped, as in G'. 

 quadrivalvis and G. australis, instead of being nearly straight as in G. tnincotn. 

 Unfortunately the stem was broken off short in all our specimens, so I can not 

 give an account of the appendages. 



Diphyopsiinae Haeckel, 1888. 



Most students recognize the two genera Diphyes and Diphyopsis. Schnei- 

 der ('98), it is true, doubts if the presence or absence of special nectophores in 

 the Eudoxids is sufficient to warrant generic separation. But I agree with 

 Haeckel ('88b), and Chun ('97b), that the occurrence in the Prayinae and in the 



