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



smooth and nearly even. Pores of both hinds with simple circular mouths, irregularly 

 scattered. Gastropores larger, less numerous, with a deeply-seated brush-like style, 

 and very thin and delicate tabulae placed at irregular intervals. Dactylopores devoid 

 of a style. Ampullse, in male stocks, ovoid, entirely immersed beneath the surface 

 of the coenosteum. Pores and ampullar more abundant on one face of the flabellum 

 than on the other. Gastrozooids cylindrical, with four club-shaped tentacles, dividing 

 at their bases into four main canals. Dactylozooids of various sizes, retracted entirely 

 within the pores when at rest. Gonophores, in male stocks ovoid, with a club-shaped 

 spadix ; one, two, or three present in each gonangium, attached directly to offsets of 

 the ccenosarcal canals. Female stocks unknown. 



2. Pliobothrus, Pourtales. 



Coenosteum branching, with a tendency to form a flabellum. Surface smooth, marked 

 with small linear openings, arranged in rows, which in the recent state contain branches 

 of the superficial ccenosarcal meshwork. Inner parts of the coenosteum very coarsely porous. 

 Pores irregularly scattered. Gastropores circular- mouthed, their cavity tubular above, 

 but expanding below into a basin-shaped chamber, without a style, often with one 

 or two tabulae. Dactylopores showing as minute openings at the tips of small tubular 

 projections, devoid of styles. Ampullae rounded cavities ; in the female very large, in the 

 male smaller ; placed deeply, often in the axis of the coenosteum. Gastrozooids flask- 

 shaped, devoid of tentacles, 1 communicating with the ccenosarcal meshwork by numerous 

 offsets arising all around their bases. Dactylozooids entirely retracted when at rest. 

 In the female a single gonophore in each gonangium ; in the male, a group of 

 gonophores (?) in each ampulla. 



3. JErrina, Gray. 



Coenosteum branching, with a tendency to form an irregular flabellate expansion. Pores 

 most abundant at the tips of the branches ; irregularly scattered. Dactylopores with 

 delicate nariform or scale-like projections, which vary much iu form, being sometimes 

 drawn out into tubes opening on one side by a slit as the pore mouth, but often 

 coalescing, so that two or three projections have a common base and form large scales 

 perforated by the pores ; devoid of styles ; scales all with a tendency to incline towards 

 the tips of the branches. Gastropores with irregularly circular mouths, often seated in 

 depressions ; with a deeply-seated style. The mouths of the gastropores frequently 

 covered by the dactylopore projections inclined more or less over them. Sometimes 

 the margin of the gastropore itself is raised up on one side into a scale inclined over 

 the pore mouth, but this is usually fused with neighbouring dactylopore projections. 

 Ampullae on both sides of the flabellum, prominent in the female ; immersed in the 



1 See note on p. 48. 



