Limitation of Genera among the Hydroida. 393 
Podocorynide. 
1. Sryzactis*, Allman, nov. gen. 
Trophosome.—Ccenosare mainly composed of a retiform hy- 
drorhiza, which consists of anastomosing tubes invested by a 
periderm; hydrocaulus rudimental (or absent?). Polypites 
claviform, with a single verticil of filiform tentacles surrounding 
the base of a conical metastome. 
Gonosome.—Gonophores adelocodonic, borne on the body of 
the polypite at the proximal side of the tentacles. 
Stylactis fucicola, Sars (sp.),= Podocoryne fucicola, Sars. 
Stylactis Sarsu, Allm.,= Podocoryne carnea, Sars. 
I have given the name of 8. Sarsi to a Hydroid which Sars re- 
garded as a form of his Podocoryne carnea with sporosacs instead of 
Meduseze (Fauna Lit. Norv. p. 7, pl. 2. fig. 5). It is, however, no form 
of Podocoryne carnea, and must be withdrawn even from the genus. 
2. Popocoryng, Sars (in part). 
Trophosome.—Ccenosare invested by a periderm, and com- 
posed of a creeping retiform hydrorhiza, with a rudimental hy- 
drocaulus consisting of very short, simple, tubular processes 
from the free surface of the hydrorhiza, and having the polypites 
developed from their extremities. Polypites with a single ver- 
ticil of filiform tentacula placed round the base of a conical 
metastome. 
Gonosome.—Gonophores phanerocodonic, borne on the body 
of the polypite at the proximal side of the tentaclest. Medusa 
with a deep bell-shaped umbrella, a small four-lipped manu- 
brium, four radiating canals, and eight marginal tentacles, with 
bulbous bases, but destitute of ocelli. 
Podocoryne carnea, Sars. 
Podocoryne (?) aculeata, Wagner (sp.), = Coryne aculeata, Wag. 
3. Corynopsis{, Allman, nov. gen. 
Trophosome.—Hydrorhiza ramified and creeping ; hydrocaulus 
rudimental or absent. Polypites claviform, with a single verticil 
of filiform tentacula surrounding the base of a conical meta- 
stome. 
Gonosome.—Gonophores phanerocodonic, borne on the body 
of the polypite at the proximal side of the tentacular verticil. 
* From oridos, a column, and aktis, a ray. 
+ In every known instance the polypites which carry gonophores in the 
genus Podocoryne are more or less arrested in their development, appa- 
rently by the exhaustion caused by their burden; but they never present 
the condition of true gonoblastidia. 
} From kopivn, a club, and dis, face (resemblance). 
