860 " THETIS " SCIENTIFIC RESULTS. 



Station 48. The stem is divided into inteinodes wliich fall' 

 roughly into two size-groups — those on the lower part of the stem 

 which bear two hydroclades, and those on the distal part wliich, 

 as a rule, bear only a single hydroclade each, and nre about lialf 

 the length of the former. The hydroclades are alternate, and 

 are set on the anterior of the stem. They are divided into a 

 series of regular internodes, each of which bears a solitary hydro- 

 theca ; but there are no internodal septa. 



The hydrothecse are set closely, but clear of each other. They 

 are deep, oval in shape, and narrowing towards the base, tiie 

 axis of the hydrotheca lying away from the hydroclade at an 

 angle of about 40°. The margin is scalloped into seven very 

 distinct teeth, of which the anterior is strongly developed and is 

 recurved ; while of the three which occur on each side, the 

 abcauline two are bent outwards. The back is entire and free, 

 almost on a level with the posterior teeth. There is no inti a- 

 thecal ridge, but the aperture between the hydrotheca and the 

 internode is guarded in front and in rear by a row of sharp 

 denticles projecting into the hydrotheca. The median sarcotheca- 

 is adnate to the hydrotheca up to the base of the recurved' 

 anterior tooth, and thence curves upwards as a free tapering 

 tube, which reaches half the height of the hydrotheca above the 

 hydrotheca! margin. It has two openings — a large aperture 

 faces the hydrotheca, and the margin of the terminal opening is 

 serrated as if it had been broken. The lateral sarcothecse are 

 adnate, saccate, roughly triangular in outline, with a broad free 

 margin which never becomes tubular at the ends. Parallel to 

 the margin, and a short distance within it, runs a chitinous 

 ridge. There are three cauline sarcothecae, which are large, and 

 are similar to the laterals in shape. One, the smallest, lies at 

 the anterior proximal end of the internode process, the others 

 are distal — one on the anterior, and the other on the posterior of 

 the internode. The distal anterior sarcothecse of all the inter-^ 

 nodes lie almost in a straight line along the stem. Gonosome. — 

 Unknown. 



Dimensions. — 



Stem internode, length 042-0'88 mm^ 



,, ,, diameter .. 0-52-0-67 ,, 



Hydroclade internode, length 0'35-0"39 ,, 



Hydrotheca, depth O-Sl-Q-Si ,, 



,, breadth at mouth (lateral aspect)... 0'21-0'22 ,, 



,, length of free portion of mesial sar- 



cotheca 012-0-21 „ 



Cauline sarcotheca, greatest width 019-0'22 ,, 



This species most nearly approaches Halicomaria proliferay 

 from which it differs in the arrangement of its hydroclades- 



