544 OLWEN M. REES. 



sisting of from one to many tentacles. The muscular system is weak 

 throughout the body. 



Genus : Corynactis. Corallimorphidse in which the body- wall is smooth. 

 The tentacles are all knobbed and are arranged in radial series so that 

 more than one communicates with each inter- or intra-mesenterial space. 

 Tentacles and mesenteries tetramerous. Gonidial groove present or 

 absent. Endodermal sphincter very weak. Mesenterial filaments devoid 

 of ciliated streak. 



Mesogloea practically homogeneous. 



Corynactis viridis (Allman, 1846). 



The word Corynactis (Greek = club-stick) refers to the shape of the 

 tentacle. 



The emerald-green ring round the capitulum was said to be character- 

 istic of C. viridis found in European seas ; this green ring was also 

 found on C. carnea (Buenos Ayres) and on C. australis (Port Phillip, 

 Australia). 



The specimens I examined were obtained from Plymouth, and were 

 collected on the Breakwater. Some were brightly coloured, green and 

 yellow, others were almost colourless. The following measurements were 

 taken from a preserved specimen from Plymouth : — 

 Diameter of pedal disk =5 mm. 

 ,, ,, column =2-5 mm. 

 ,, ,, oral disk =4 mm. 

 Length of column =5-5 mm. 

 ,, ,, tentacle =1 mm. 



The external appearance of C. viridis has been described by many of 

 the older writers. In 1884 Andres describes it in UAttinie in page 266. 

 In the report on Actiniaria dredged by H.M.S. Challenger, 1873-76, 

 Hertwig gives the arrangement of the mesenteries. The first account 

 was written by Allman in the Annals and Magazine of Natural History 

 in 1846. Allman obtained his specimens near low- water mark in the 

 pools left by the retiring tide in Crook Haven, Co. Cork. One of his 

 specimens was a fairly large one measuring -5 inch across the tentacular 

 disk. 



In Allman's specimen the colour of the tentacular disk was bright 

 green, except for a circle of radiating brown striae which surrounded 

 the mouth at a short distance from its margin. The stems of the tentacles 

 were of a sienna colour and their extremities were of a bright rose. He 

 found varieties which were not uncommon, in which the green colour 



