324 ERNEST AVAEEEN. 



brown in colour and reaches a height of about one-quarter of 

 an inch. The hydroid is interesting in a number of ways ; it 

 exhibits characters strikingly intermediate between those of 

 the Eleutheroplea and the Statoplea, also, the same 

 stem frequently bears both male and female gonangia, and 

 when such is the case the male appear to be invariably placed 

 at the distal end of the series. 



Trophosome. — The hydrorhiza may form a very close 

 meshwork ; sometimes it is so close that there are practically 

 no meshes and the whole constitutes a sheet composed of vermi- 

 form tubes more or less coalesced. 



Average diameter 0"127 nnn., thickness of perisarc 14^. 



The hydrorhiza is frequently found attached to the same 

 species of coralline alga as that which is so frequently 

 attacked by a hydroid about to be described (Aglaophenia 

 parasitica). This latter species sends suckers into the sub- 

 stance of the alga; but such is not the case with Paragattya 

 intermedia, which, nevertheless, can fasten itself firmly to 

 the smooth, hard surface of the coralline. 



Hydrocaul us. — Pinnate stems spring from the hydrorhiza. 

 The main stem consists of 2-5 basal joints, and above them it 

 is divided into regular internodes by oblique nodes, and each 

 bears a hydrotheca. It is somewhat zig-zag. The pinna3 are 

 alternate, each internode of the main stem bearing one lateral 

 branch, which springs from the process carrying the supra- 

 calycine nematophores (PI. XL VII, fig. 27, h.). The two proxi- 

 mal internodes of a pinna carry no hydrotheca? ; the remainder, 

 of which there are generally only two or three, resemble those 

 of the main stem. 



Nematophores; one above (text-fig. 16, C) and one below (D) 

 each hydrotheca in the middle-line, and two lateral or supra- 

 calycine nematophores [E). 



The sarcostyle below the hydrotheca is lodged in a short 

 trough-like sarcotheca ; the one above the hydrotheca is con- 

 tained in a fairly stout cup-shaped sarcotheca. The two 

 lateral nematophores are set on processes from the distal ends 

 of the stem-internodes, and they are distinctly jointed at their 



