692 R. KIEKPATRTCK. 



dencv. It is surprising to realise that the extensive crust of 

 Merliaon the Denclrophyllia is the product of a very thin 

 incrnsting siliceous sponge, and, again, it is equally surprising 

 to observe the great bulk of the masses of calcocytes in 

 proportion to the rest of the tissues. 



The English colleague already mentioned, who is, I believe, 

 publishing a report on the dried calcareous skeleton of an 

 oi'ganism which he thinks is Merlia, considers it to be a 

 Foi-aminiferan. I think the specimen comes from the West 

 Indies. Assuming the skeleton to be that of a Merlia, in 

 which case it will be part of a sponge, the existence of Merlia 

 at Porto Santo may have been due to embryos being carried 

 by the Gulf Stream. On the north shore of the island 

 Columbus collected Entada beans, which led him to speculate 

 on the existence of land beyond the western horizon. The 

 currents which carried the Entada beans might also carry the 

 Merlia embryos which would settle on the first submarine 

 peaks they would come to after their long voyage. 



The theory that Merlia is a local survival from the periods 

 when the coral reefs of Ilheo da Baixo were laid down seems 

 to me more probable, however, than that of the West Indian 

 origin of the sponge. 



(6) Systematic Position of Merlia. 



The calcareous skeleton may be a character of no great 

 importance fi'om the systematic point of view. 



The canal system — in spite of its novel or hymenopylous 

 character — and the siHcoous skeleton undoubtedly resemble in 

 many respects the types commonly found in Monaxonellid 

 sponges. 



The calcareous skeleton is, I believe, an accidental and 

 acquired character due to the activities of cells usually con- 

 cerned in the metabolism of food and not occupied with skeleto- 

 genous functions, these latter belonging to a wholly different 

 type of cells — the scleroblasts. Merlia,then,isaMonaxonellid 



