54 On the Atractylis coccinca of T. S. Wrujht. 



Tropliosomp. — The hydrocaulus consists of a number of 

 short stems \-\ inch in length (slender, somewhat contorted, 

 imbranched, or'with small offshoot bearing a hydranth), which 

 arise at short intervals from a 

 creeping and anastomosing 

 Iiydrorhiza, which resembles 

 the stems. The hydranth 

 makes an obtuse angle with 

 the stem. It is closely in- 

 vested up to the roots of the 

 tentacles by a hydrothecal ex- 

 pansion of the perisarc, but is 

 not retractile into it. The 

 tentacles are 10-12 in number, 

 short and straight, disposed in 

 a single verticil round the 

 bluntly conical hypostome. 

 The perisarc is straw-coloured, 

 and is wrinkled transversely 

 where it expands to cover the 

 hydranth. The colour of the 

 hydranth is pink, turning to 

 white at the tip of the hypo- 

 stome. The tentacles are 

 translucent white ; the coeno- 

 sarc pink to scarlet. 



Gonosome. — The gonophores 

 are sporosacs. They are globu- 

 lar and arise from the hydro- 

 rhiza, to which they are at- 

 tached by a slender pedicel. 

 They are invested by a 

 chitinous covering which is 

 continuous with the perisarc. 

 There is a short blunt spadix, 

 in the outer layer of which the gametes are matured. 



The gonophore resembles in structure that of Garveia 

 wwfa/2Sj as figured by Allmau (' Gyninoblastic Hydroids,' i. 

 p. 44). 



The colour of the gonophore is translucent white ; the 

 spadix is brick-red ; the gametes pink. 



Wrightia coccinea was taken by Wright at Inch Garvie, 

 Firth of Forth, on the roots of Laminaria saccharina, and by 

 the writer at Hunterston Perch, near Fairlie, Firth of Clyde, 

 in 12 fath., on Tuhularia, and in Castle Bay, Little Cumbrae, 

 in 15-20 fath., also on Tuhularia. It is common where it 



Wrightia coccinea. 



