SOME OBSERVATIONS ON CONVOLUTA 

 ROSCOFFENSIS. 



By Horace Athelstan Wager, A.R.C.S. 



Conz'oluta roscoffoisis is a small marine worm of the Tur- 

 bellarian group — a green plant animal as described by Professor 

 Keeble in his little book on Plant- Animals. Hitherto it has, I 

 believe, been recorded only from Europe, but both Dr. Warren 

 and I have found it on the Natal coast. This species appears to 

 be somewhat different from the European one as described by 

 Professor Keeble, and is probably a degenerate form. It lives 

 gregariously actually in the water, forming a dark olive-green 

 scum on the sandy edge of small rocky pools just below high- 

 water mark. It occurs at Umkomaas on a small stretch of about 



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20 yds., but not anywhere else in the vicinity of Umkomaas, 

 although many places just as suitable, apparently, are quite 

 frequent. This is rather surprising, as their beds are swept 

 twice a day by the sea and the dissemination should be easy. The 

 European species is found on moist patches of sand between tide 

 marks, but not usually actually in the water. It is also very sensi- 

 tive to vibration- — an approaching footstep or an incoming wave 

 causing nearly all of them to disappear below the surface of the 

 sand. The Natal species, however, does not appear to be at all 

 sensitive to vibration. They do not disappear when approached 

 or even when subjected to greater vibration. The first tidal water 

 that reaches them swills them all out of the pool and scatters them 

 over the sand, and they then disappear below the sand. They 

 are very delicate animals, as I found great difficulty in carrying 

 them alive for any distance unless in a relatively large amount of 

 sea-water. Also, they quickly die in an uncovered vessel of 

 sea-water, probably owing to concentration of the water from 

 evaporation, as the occasional addition of a little fresh water 

 keeps them alive. 



The structure of the animal appears to be rather more simple 

 than in the European species. They have a very graceful gliding 

 motion, but with a good deal of euglenoid movement. There is a 

 mouth and gullet, but no alimentary canal. The whole animal is 



