22 ME JAMES RITCHIE 



greatest diameter. It has five pairs of adiiate costae, each bearing from ten to twelve not 

 quite tubular denticles along its length and an apparently unpaired, partly free, costa at 

 the proximal end. On the corbula peduncle there is one hydrotheca. 



Locality, etc. — The colonies were growing on a sponge, and were dredged at the 

 entrance to Saldanha Bay, Cape Colony, in 25 fathoms of water. Date, 21st May 1904. 



Plumularia echinulata, Lamark, 1836. 



Several colonies, the largest 3 cm. in height, were found growing on sponges in the 

 same locality as P. pinnata. The specimens difter somewhat from the type described 

 by HiNKS (1868) but seem to form a connecting link between P. echinulata, type 

 and P. ec/imi<7oto, var. jjinvioiojf/es of BiLLARD (1904, p. 191 et seq.). The following 

 points indicate a close relationship to the latter : — Stem internodes in the proximal 

 portions of the colony sometimes bearing two hydroclades, while in the distal internodes, 

 and more generally throughout the colony, only one hydroclade per internode is the 

 rule ; intermediate internodes in the hydroclades absent in the specimens examined ; 

 supracalycine sarcostyle unprotected by a nematotheca, as described by Hinks ; 

 hydrothecse deep ; gonangia borne on stem. On the other hand, the fact that the 

 margin of the hydi'otheca does not reach the level of the succeeding node, and the 

 presence of well-marked and frequent spines on the gonangia, indicate affinities with 

 Billard's type. 



The state of the material prevented observations on the condition of the axillary 

 nematophores from being made. 



Locality, etc. — Growing on sponges, coaling jetty, Cape Town Docks. May 

 1904. 



Plumularia magellanica, Hartlaub, 1905. (PI. III. fig. 1, 1a.) 



The specimens collected by Mr Bruce difter somewhat in the structure of their 

 hydroclades from the specimens of this peculiar species described by Hartlaub, but 

 the difference is not of specific value. As in Hartlaub's case, material is scarce. 



The most complete colony is 1 5 mm. in height, and consists of a stem " 1 5 mm. in 

 diameter, divided by straight nodes into irregular internodes, each of which bears near 

 its middle a single hydroclade. The hydroclades arise alternately from the stem nodes 

 and are comparatively short — about 1 mm. They are set upon a small process of 

 the stem, from which the first thecate internode is separated by a narrow, somewhat 

 ring-like, athecate internode with slanting nodes. The thecate internodes are narrow at 

 the base, and gradually widen distally until they finally seem to end in a rather shallow 

 cup with expanded walls. From below this cup, and free from it, there arises in the 

 distal portions of the colony a single short process, which bears again an expanding 

 thecate internode from beneath whose hydrotheca another free process is given off", and 

 so on, until each hydroclade bears from two to four or even five hydrothecse. The 



(rot. soc. edin. trans., vol. xlv., 540.) 



