A COLLECTION OF HYDEOIDS. 279 



brightly coloured as above described. The tentacles are all 

 capitate, and are arranged in one series at the base of the 

 hypostome ; they arise close together from the body of the 

 hydranth, and they are too numerous to form a single verticil. 

 There are some 28-35. 



The following are the measurements of a preserved typical 

 specimen. Total height of polyp 0"8-4mm. ; diameter, imme- 

 diately above the verticil, 0"58 nun. ; diameter of the capi- 

 tulum of a tentacle 0*15 mm. 



Gonosome. — The reproductive bodies (fig. 8, p/.) are pro- 

 duced in clusters on short outgrowths from the body of the 

 hydranth just above the circle of tentacles. These bodies 

 are shown in section in fig. 9. 



In none of the specimens collected were the reproductive 

 bodies mature, and consequently it is not possible to state 

 whether free medusas are formed. 



General histology. — The perisarc of the hydrocaulus 

 dips into a groove at the base of the hydranth, and then 

 extends for a short distance upwards over a modified band of 

 ectoderm (fig. 9, 2^-)- 1'^^ capitulum of a tentacle possesses 

 both large and small nematocysts ; the former measure 19 /ii 

 in lengtli and 11 /i in breadth, and the latter 9 /n and 4 ^t 

 i-espectively ()i.). 



The endoderm of the hypostome {cJnj.'] is thick and com- 

 pact, with numerous small nuclei, which have a special 

 affinity for stains. Below the hypostome there are pendulous 

 lobes of large cells {(jl.c) with large pigmented granules, 

 and there are also a small number of oval cells {ov.c.) which 

 stain readily and appear to consist of somewhat dense and 

 homogeneous protoplasm. The usual vacuolated cells {v.c.) 

 occur at the base of the hydranth, and skeletal septate endo- 

 derm runs up the tentacles. 



Systematic Position. — The present species is clearly closely 

 allied to Clavatella jirolifera Hi-licks'^ of the British 

 coasts; it agrees Avith it in the tentacles being all capitate 



' Hinoks. T., ' A History of the Britisli Hydroid Zoophytes," 1868, 

 p. 73. 



