A COLLECTION OF HYDROIDS. 285 



The polyp has a chalky-white area around the mouth, and 

 the body below is red. The perisarc is pale yellow, and in 

 the hydrorhiza it is smooth, while in the hydrocaulus there 

 may be a few irregular annulations. 



Around the mouth there is a whorl of four to six simple short 

 capitate tentacles. The number of pinnate tentacles is very 

 variable, 10-18, and they appear to be irregularly scattered 

 over the body, although a verticillate tendency is assigned to 

 them by Allman.^ The number of capitate ramuli on the 

 tentacles varies from 6-14. 



The whole length of the tentacle is occupied by a very 

 regular septate endodenii. 



All the material collected has been carefully searched for 

 the gonosome, but it is regretted that none has been found. 

 In the description given by Allman the gonosome is stated to 

 be unknown. 



(9) Asyncoryne ryniensis g. e. sp. n. (PI. XLVI, figs. 13 



-17.)^ 



Only two small colonies of this interesting hydroid have 

 been found. They were obtained from Park Rynie, as the 

 specific name implies, and were growing on the surface of 

 polychfet worm-tubes. Although the polyps are large, being- 

 several millimetres in length, yet they were overlooked in 

 the living condition, and only after fixation with corrosive 

 sublimate were they detected. It is hence probable that 

 they are exceedingly transparent when alive (PI. XLVI, fig. 13). 



Tkophosome. — The hydrorhiza is a creeping stolon which 

 appears to branch sparingly. 



The diameter is about 0"24 mm. The perisarc is frequently 

 remarkably inflated, being made up of thin layers more or 

 less widely separated from one another. When not inflated 

 it has a thickness of about 8"9 fi. 



Hydrocaulus. — The hydrorhiza produces at irregular 

 intervals very short upright stems bearing a single elongated 



' AUmaii, G. J., ' A Monograph of the Gymnolilastic Hydroids,' 1872, 

 Part II, p. 380. 



