84 MR JAMES RITCHIE 



middle of each internode there arises a single hydroclade. In no case has more than 

 one hydroclade per internode been seen. The hydroclades, which are set on short 

 processes of the stem internodes, lie alternately in two planes, these planes being 

 so set forward that the hydroclades appear to arise from only one side of the 

 stem. They leave the stem at acute angles (30 to 45), and are divided into 

 equal internodes 0'25 mm. long, each of which bears a hydrotheca one small triangular 

 athecate internode separating the first thecate internode from the stem process In 

 some cases secondary hydroclades are developed from the side of a hydroclade inter- 

 node at the level of the base of the hydrotheca. No internodal septse are present, 

 but the internode bulges proximally to form a support for the hydrotheca. The 

 hydrothecse are cup-shaped, moderately deep, even-rimmed, and for a short distance 

 distally they are free from the internode. They are closely approximated, the margin 

 of a hydrotheca being on a level with the succeeding node. Nematophores are absent 

 from the stem, from the stem processes, and from the athecate internodes at the origin 

 of the hydroclades, but one small, shovel-shaped nematotheca occurs in the median 

 portion of the internode just below each hydrotheca, while in the angle between the 

 hydroclade and the free rim of the hydrotheca is a median, unprotected sarcopore. 



Gonosome. Gonothecse about 1 mm. in length occur in parallel rows along the 

 stem, apparently arising on the inner side of the hydroclade-bearing processes. They 

 are ovate, with somewhat flat tops, and are very shortly stalked. The gonothecae are 

 seldom smooth, the walls being generally strengthened by seven regular longitudinal 

 ridges, which terminate distally in one or two more or less pronounced spines. 



Locality, etc. Growing on a sponge from the entrance to Saldanha Bay, Cape 

 Colony; 25 fathoms. Date, 21st May 1904. 



Antennularia hartlaubi, n. sp. (PL III. fig. 4, 4A, 4B.) 



Colonies growing on a sponge in thick bunches, with thick fascicled stems which, 

 about 1 cm. from the base, break up irregularly into smaller, still fascicled branches, 

 these finally breaking up into long simple twigs. The latter are divided by straight nodes 

 into regular internodes 0'5 mm. long, each of which bears three equally distant hydro- 

 clades so arranged that those on one internode exactly alternate with those on the 

 internodes above and below, a hexastichous arrangement thus being produced. The 

 hydroclades are borne on stout processes of the branch internodes 0'15 mm. long, and 

 are divided into unequal internodes which are alternately long and thecate and short 

 and athecate two athecate internodes separating the first thecate internode from the 

 supporting process. Sometimes, however, two athecate internodes are developed 

 between a hydrotheca-bearing pair. Each internode is marked by two strong internal 

 septa, one proximal, the other distal ; but in the longer internodes two more are 

 sometimes developed, one opposite the base of the hydrotheca, the other a little lower. 

 The hydrothecae are shallow, even-rimmed, resting on a broad ledge of the internode 



(ROY. soc. EDIN. TRANS., VOL. XLV., 542.) 



