332 ERNEST WAKREN. 



(29) Aglaoplienia parasitica sp. n. (PI. XL VIII, 



figs. 28-32.) 



This hydroid occurs very abundantly at Scottburgh among 

 the large masses of red coralline sea-weed. It is of a dark 

 brown colour, and the pinnate stems reach a height of about 

 1 inch. 



Trophosome. — Hydrorhiza is a creeping stolon spai'ingly 

 branched, it grows on the surface of the coralline weed, into 

 which it sends suckers. 



Diameter about 0*25 mm., thickness of perisarc 30 /x. 



Hydrocaulus. — Simple pinnate shoots; the basal portion 

 without pinn^ is short, and proxinially is transversely 

 jointed, while distally there may be two or three oblique 

 *joints. The portion bearing pinnre is divided into regular 

 short internodes by transverse or slightly oblique joints, each 

 joint bearing a pinna on a short thick process. Pinnas 

 alternate, divided into internodes by transverse nodes. 



Nematophores : mesial nematophore long and cylindrical, 

 adnate for about half its length to the hydrotheca (PL XL VIII, 

 fig. 28 m.n.), widely separated from the margin of the hydro- 

 theca, and approximating to a horizontal position ; lateral 

 nematophores rather short, cylindrical, and extending to about 

 the level of the margin ; cauline nematophores cup-shaped, 

 three in number, situated at the base of the pinnae (text-fig. 

 17,5). 



Nematocysts of mesial nematophore about 12'4/i in length 

 and 3*1 yi in breadth. 



Diameter of stem below pinnate portion 0"23 nun., thickness 

 of perisarc 48 f.i ; diameter in the middle of the pinnate 

 portion 0*21 mm., length of stem-internode 0182 mm. 



Diameter of hydrocaulus of pinna from the side O'llo mm., 

 from the front 0"081 mm., thickness of perisarc 16 /.i, length 

 of internode of pinna 0*212 mm. 



Hydrotheca. — Distal portion and mouth wide, proximal 

 portion rather narrow. Margin provided with thirteen teeth, 

 one median and six lateral ; the third and fifth point inwards, 

 and the second and fourth point outwards (fig. 29) ; the 



