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



divided in two by the longitudinal muscles art; turned over outside (like the brim of 

 a hat). The very powerful muscles of the mouth and of the stomach he in numerous 

 folds projecting internally (figs. 2, 12). 



The eight narrow radial canals (fig. 3, cr) which run at equal distances from the 

 fundus of the stomach (fig. 3, go) to the periphery, are there opened into a narrow 

 annular canal (fig. 3, cc ; figs. 5-8, cc). In the transverse section these walls show 

 numerous thick folds and tufts (<.!])), which proceed from the distal margin of the 

 canal, and project freely into its lumen. As usual, the outer or umbra! wall of the 

 annular canal, which lies close to the marginal portion of the gelatinous substance of 

 the umbrella (//), is covered by a flat, tabular epithelium (dn), whilst, on the other 

 hand, the remaining portion or the subumbral wall is covered by high, cylindrical 

 epithelium (dw). The latter also lines the tufts or folds of the lower wall of the 

 canal. At their basal end (which is turned from the lumen of the canal), the very 

 high cylindrical cells of the tufts contain granules of black pigment, enclosing a 

 nucleus. These pigmented tufts (which resemble the intestinal tufts of the verte- 

 brata) have probably secretive or excretive functions. (Comp. PI. IV. figs. 5-8, and 

 explanation.) 



The eight genitalia or reproductive glands (figs. 2-3, sc) hang in the proximal halves 

 of the eight radial canals, as visible sacculations from it (four perradial and four inter- 

 radial). These appear as wide, fluted, thick-walled, egg-shaped, or fusiform sacs. A 

 radial mesogonium (or genital mesentery) rises in the middle of the subumbral wall of 

 each sac, as a thick vertical fold of the subumbrella, which passes from the basis of the 

 stomach to the umbrella margin (fig. 3, wr). These eight mesogonia attach the corners 

 of the stomach, halve the eight genitalia, and divide the space of the umbrella cavity into 

 the eight above-mentioned umbrella funnels, or the peripheric niches of the umbrella 

 cavity. 



Pedis, 1 Haeckel, 1879. 



Trachynernidaa with eight genitalia in the course of the eight radial canals, between 

 which blind centripetal canals run from the annular canal. Genitalia connected with the 

 basis of the stomach by eight radial mesogonia or leaf-shaped mesenterial bands. Oral 

 cavity with eight invaginated oral funnels, and sixteen evaginated side pouches. 

 Tentacles with sucking-cups very numerous, closely crowded together in several rows 

 above each other on the umbrella margin. Numerous (8 or 16 ?) auditory clubs. 



The genus Pedis is strikingly distinguished from both other genera of Peetyllidre by 

 its blind centripetal canals, which run out in large numbers from the annular canal (as 

 in Olindias among Petasidee, Glossoconus and GJossocodon among the Liriopida;, Carmaris 



1 n.r,KTi:, hardened, stiffened. 



