Limitation of Genera among the Hydroida. 353 



Podocorynidae. 

 1. Stylactis*, Allman, nov. gen. 



Trophosome. — Ccenosarc 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 {s^.),-=^Podocoryne fucicola, Sars. 



Stylactis Sarsii, AWm. , = Podocoryne carnea, Sars. 



I have given the name of S. Sarsii to a Hydroid which Sars re- 

 garded as a form of his Podocoryne carnea with sporosacs instead of 

 Medusae (Fauna Lit. Norv. p. 7, pi. 2. fig. 5). It is, however, no form 

 of Podocoryne carnea, and must be withdrawn even from the genus. 



3. Podocoryne, Sars (in part). 



Trophosome, — Coenosarc 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 tentaclesf. 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 acukata^Wag. 



3. CoRYNOPSis J, 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 oTvKos, a column, and oktIs, a ray. 



t In every known instance the polypites which carry gonophores in tlie 

 genus Podocoryne are more or less arrested in their development, appa- 

 rently by the exhaustion caused by their burden j but they never present 

 the condition of true gonoblastidia. 



X From Kopvvq, a club, and o^i5,face (resemblance). 



