1334 THE VOYAGE OF H.M.S. CHALLENGER. 



shell ; three edges of the horn wing-shaped and dentated. Thorax hemispherical, in the middle 

 zone with three conical wings, which are half as long as the thorax, and curved downwards. 

 Pores hexagonal, roundish, twice as broad in the inflated abdomen as in the thorax. Mouth 

 constricted, with a corona of from fifteen to eighteen conical, divergent, curved feet, similar to the 

 thoracic wings. 



Dime7isio7is. — Length of the three joints, a 0-02, b 0-06, c 01 ; breadth, a 0-025, h 01, c 014. 



Habitat. — Central Pacific, Station 265, depth 2900 fathoms. 



3. Pterocodon favosus, n. sp. 



Shell ovate, with two slight strictures. Length of the three joints = 1:2:2, breadth = 2:4:4. 

 Cephalis hemispherical, with a conical horn of twice the length, Three wings of the thorax equal 

 to those of the preceding species. Pores regular, circular, hexagonally framed, of equal size in 

 the thorax and abdomen. Mouth constricted, with a corona of nine straight, conical, nearly 

 vertical feet. 



Dimensions. — Length of the three joints, a 0-0025, b 0-05, c 0-05 ; breadth, a 0-05, b 0-09, c 0-1. 



Habitat. — Central Pacific, Station 272, depth 2600 fathoms. 



Genus 590. Dictyocodon,^ Haeckel, 1881, Prodromus, p. 435. 



Definition. — T h e o p i li d a (vel Tricyrtida triradiata aperta) with three latticed 

 free lateral wings on the thorax, and numerous latticed terminal feet around the mouth 

 of the abdomen. 



The genus Dictyocodon, one of the most elegant among the Nassellakia, differs 

 from the preceding Pterocodon in the fenestration of the three lateral wings of the 

 thorax, and the numerous terminal feet of the abdomen. It may be derived from 

 Dictyoceras by development of regular lattice-feet around the terminal mouth. 



Subgenus 1. Dictyocodella, Haeckel. 

 Definition. — The three lateral lattice-wings arise from the thorax alone. 



1. Dictyocodon annasethc, n. sp. (PL 71, fig. 11). 



Shell with two deep strictures. Length of the three joints = 2:5:4, breadth = 1:5:6. 

 Cephalis subspherical, with a very large, three-sided prismatic horn of three times the length, 

 bearing at the base some smaller accessory spines. Thorax nearly conical, with three large, inflated, 

 triangular lattice-wings, the upper edge of which (the cortinar rod) descends obliquely, and is larger 



' Dictyocodon = Net-bell ; IIktvov, xalut. 



