6 THOMSON, The Pennatulaceae of the Cape of Good Hope. 



pinnules of the tentacles are easily seen. The rachis is 

 of a fairly bright red colour, but this coloration is mainly 

 produced by the spicules of the calyces of the autozooids, 

 the siphonozooids appearing as minute, circular, colour- 

 less areas between them. The calyces of the autozooids 

 project 2 mm. above the surface of the coenenchyme, and 

 the bright red spicules on their surface render them very 

 conspicuous. The two projecting points of the calyces 

 are very prominent in these specimens. The stalk is 

 much paler in colour than the rachis, being a pale 

 yellowish-red. 



The dimensions of a colony are as follows : — 



Length of specimen 95 mm., length of stalk 21 mm., 

 length of rachis including apical autozooids 74 mm., length 

 of anthocodiae 6 mm., height of calyces about 2 mm. 



The more important points in the determination of 

 these specimens are as follows : — 



The autozooids are perfectly radially arranged, and 

 with one exception there is no trace of a groove on the 

 ventral surface of the rachis. The calyces of the auto- 

 zooids show two prominent and six much less con- 

 spicuous teeth, the calyces and teeth are, however, by no 

 means so marked as in the genus Echinoptilum. The 

 anthocodiae of the autozooids have spicules, this being a 

 character in which the specimens resemble Echinoptilum 

 but differ from typical Actinoptila. In Echinoptilum 

 Macintoshii, Balss, spicules occur on the tentacles, but 

 not on the polyp wall. 



Transverse sections show that the arrangement of the 

 internal canals is that typical of Actinoptilum or Echinop- 

 tilum. The external transition between stalk and rachis 

 is quite sharp. The stalk in transverse section is not, 

 however, circular as described for Echinoptilum. The 

 ratio length of stalk to rachis is 1 : 2 or 1 : 3. 





