REPORT ON THE SIPHONOFHOR^. 179 



dorsal face, or the dorsal circumference of the ostium, is provided with four descending 

 lobes or triangular teeth, which are wanting or but slightly indicated in Hippopodius. 

 The two basal apophyses of the lateral ventral wings are also more prominent than in 

 the latter, and the mouth of the nectosae therefore surrounded by six teeth. The 

 general form of nectophores in Pohjplnjes, therefore, is intermediate between that of 

 Hippopodius and of Vogtia. Another difference seems to be indicated by the monoclinic 

 cormidia and the position of the gonophores, which are attached to the base of the 

 siphons in the two latter genera, separated from it by an interval in Polyphyes. 

 (Compare the preceding description of Hippopodius.) 



The typical species of this genus, described in the sequel, was observed by me in 

 1866 in the Canary Islands, and detached nectophores of it found again in the Challenger 

 collection (Station 352, Tropical Atlantic). The characteristic form, however, of the 

 nectophores, with the six strongly prominent teeth, figured in PL XXIX., is more 

 developed in the specimens from Station 352 than in those which I observed 

 myself in Lanzerote. These latter approach more to the southern Mediterranean form 

 described by Kolliker as Hippopodius neapolitanus (4). 



Polyphyes ungulata, n. sp. (PI. XXIX. figs. 1-8). 



Habitat. — Tropical and Subtropical Atlantic; Station 352, April 13, 1876; 

 lat. 10° 55' N., long, 17° 45' W. Surface. 



Canary Islands, Lanzerote; December 1866 and January 1867 (Haeckel). 



Nectosome (fig. 1). — The swimming column is composed of five or six pairs of 

 obliquely opposed nectophores, the size of which increases from the rounded top towards 

 the bevelled base. The general outline of the compressed nectosome is ovate seen from 

 the broad side, more lanceolate seen from the narrower side. The connection of the 

 united nectophores is very firm, each embracing the base of the superjacent nectophore 

 by the two lateral wings of its ventral groove ; and also the opposite basal apophyses of 

 the opposite superior nectophore. 



Nectophores (figs. 1, 2, lateral view; fig. 3, apical view; fig. 4, basal view; fig. 5, 

 ventral view; fig. 6, dorsal view). — The largest neetocalyces have a diameter of 15 to 

 20 mm., and possess the form of an inverted horse's hoof, the lower face of which is turned 

 upwards. Five faces may be distinguished in the wedge-shaped horse-shoe, which 

 represents an obliquely bevelled segment of a cone ; an inferior basal face, an exterior 

 dorsal face, an interior ventral face, and two paired lateral faces. The basal face, directed 

 obliquely downwards and outwards, contains the reniform or subcircular mouth of the 

 nectosae (figs. 3, w, 4) and the creseentic velum (v) ; it is surrounded by six prominent 

 paired teeth, four dorsal and two ventral triangular apophyses ; the two lateral dorsal 



