450 DR. p. F. HARMER ON THE 



produced from floating statoblasts and those which have developed 

 from sessile statoblasts. 



It is believed by most recent authorities that AlcyotieUa is not 

 geiierieally separable from Phimatella. Alcyonella is character- 

 ised by its compact form, resulting from the airangement of its 

 crowded, more or less paiallel, tubes, more or less at right angles 

 to the substratum. It has been suggested that this habit of 

 growth is largely, if not entirely, the result of the simultaneous 

 germination of a number of statoblasts situated close together. 

 But I am not aware of the existence of any experimental 

 evidence to show whether a large colony of Alcyonella fungosa 

 can be produced by the germination of a single statoblast. Some 

 evidence that the completely paiullel tubes of the typical /^m(/osa- 

 form owe their arrangement to want of room, is given by the fact 

 that the peripheral parts of Si fuiigosa-co\or\y may have the form 

 of the var. coralloides, which is characterised by a looser habit of 

 growth. 



The conclusion that '■'■Alcyonella" is merely a form of Phima- 

 tella seems to me to be well founded. The only generic distinction 

 which can be maintained is the habit of growth ; and in this 

 character P. fungosa var. coi^alloides is intermediate between 

 '■'•Alcyonella'^ and Phimatella. Kraepelin (87) has gone so far 

 as to regard P . fungosa as merely a form of P. repens, which is 

 termed by him, on insufficient nomenclatorial grounds, P. jooZy- 

 morplia. In this conclusion he was at one time criticised by 

 Braem (90), who pointed out dilSerences which led him to believe 

 that P. fungosa is specifically distinct from P. repens. Braem 

 has more recently (11, p. 9) retracted this view, and he now 

 regards P. repens and P. fungosa as varieties of one species. 



The specimens which may be referred to the P. fungosa type 

 were sent on May 31, and were received alive, with their 

 polypides in full vigour. As has been pointed out above, they 

 were taken from the pool which supplies the system, and I have 

 not seen specimens from the pipes themselves, whei-e great trouble 

 has been caused. Mr. R. H. ISTewill, to whose kindness I owe 

 the specimens and as much information as he was able to give, 

 has, however, assured me that the specimens which blocked the 

 pipes and ram resembled those which had been taken from the 

 pool supplying the system. There is thus a strong presumption 

 that the specimens examined belonged to the same species as 

 those which occurred in the pipes ; a conclusion which is rendered 

 all the moi'e probable by the fact that this foini has a very 

 characteristic habit of growth, which Mr. Newill cannot have 

 failed to notice. 



I have 1 ad some difficulty in deciding whether the specimens 

 in question should be regarded as typical examples of P. fungosa 

 or should be referred to its variety coralloules (= Pliimatella 

 coralloides Allman, cf Allman, 56, p. 105). In the more central 

 parts of the masses the tubes have the/«?igfos«-arrangement. In 

 the more peripheral parts of the mateidal they may be less 



