KEPORT ON THE SIPHONOPHORvE. 153 



tains specimens of this species, taken in different parts of the Pacific (e.g., Stations 175, 

 222, 265 to 279, &c). 



A second species may be the Mediterranean Diphyopsis campanulifera, described as 

 Diphyes campanulifera by Eschscholtz, first observed by Quoy and Gaimard in the 

 Strait of Gibraltar. 



A third species is described in the following lines as Diphyopsis compressa. It 

 inhabits the Tropical and Subtropical Atlantic. The Challenger collection contains many 

 specimens of it, taken between Stations 327 and 353. 



Diphyopsis compressa, n. sp. (Pis. XXXIII. , XXXIV.). 



Diphyes compressa, Hid., 1866, MS. Canar. 



Habitat. — Tropical and Subtropical Atlantic, Stations 327, 334, 348, 352a. 

 Canary Islands, Lanzerote, December 1866 (Haeckel). 



Nectophores (fig. 1, the two nectocalyces in their natural connection, seen from the 

 left side ; fig. 2, from the ventral side ; fig. 3, from the dorsal side). — The two large 

 swimming bells are of nearly equal size and similar form ; their usual length is between 

 25 and 30 mm., the breadth between 10 and 15 mm., the thickness 5 to 7 mm. ; the 

 first or apical nectophore, however, is a little larger, longer as well as thicker, than 

 the distal one. The former encloses on its ventral side a campanulate hydrcecium 

 (and above its top a somatocyst) ; the latter an incomplete subcylindrical hydrcecial 

 canal. 



Apical Nectophore. — The first, superior, anterior or proximal nectocalyx, appears in 

 the lateral view (fig. 1) as a broad triangle, the dorsal side of which (nd) is the longest 

 and slightly convex ; the opposite ventral side (nv) is more convex, one-fifth shorter, and 

 twice as long as the obliquely bevelled basal side. The ratio of the three sides therefore 

 is = 5:4:2. Seen from the ventral side (fig. 2), or from the dorsal side (fig. 3), the 

 nectophore appears as a very long and narrow isosceles triangle, the two equal lateral 

 sides of which are four times as long as the basal side. Seen from the basal face (fig. 8) it 

 appears nearly rectangular, three times as long as broad, with a small triangle imposed on 

 the dorsal side. The exumbrella therefore has the form of a bilateral pentagonal pyramid, 

 which is very strongly compressed from both sides. Its surface exhibits five prominent 

 ridges, one odd dorsal and two pairs of laterals, meeting in the slender pointed top of the 

 nectophore. The odd dorsal ridge (figs. 1, 3, nd) runs in the median dorsal line of the 

 exumbrella and ends below in the odd dorsal tooth of the mouth of the nectosac. The 

 two dorso-lateral ridges run along the lateral faces of the nectosac and end below in the 

 smaller dorso-lateral teeth of its mouth (n 1 , n 2 ). The two ventro-lateral ridges run along 

 the ventral face of the hydrcecium and end in two small ventral teeth (fig. 8, « 5 no'') 



(ZOOL. CHALL. EXP. — PART LXXVII. — 1888.) Hhhh 20 



