ON THE BRITISH SPECIES OP ORISIA. 



145 



C. ramosa, n. sp. Fig. 11. 

 Some of the characteristics of this species are well exhibited 

 by the formula' — 



=W 

 =(3+a:) 



'=(l+:r) 

 =(4+2r+a:) 

 =ilO+r,+x) I 



The branching is seen to be very similar to that of C. acu- 

 leata, but the tendency, already manifested by that species, to 

 develop more than one branch from an internode, is here 

 carried much further, so that a considerable proportion of the 

 internodes have two branches each, while the terminal inter- 

 nodes, if the colony is well grown, will be found to have at 

 least two each. 



The rule relating to odd- and even-numbered internodes, so 

 characteristic of C. denticulata and of C. eburnea, here 

 breaks down altogether, as, indeed, was the case to a consider- 

 able extent in C. aculeata. Odd-numbered internodes are 

 not much commoner than even-numbered ones, and either kind 

 may produce one or more branches, or be altogether branchless. 

 The first branch of an internode is, however — as in other 

 species — nearly always developed on the side of the basal 

 zooecium, and the last zooecium of an internode is very often 



' It is obvious that, in the case of the ovicell-bearing internodes, some of 

 the branches are given off above the ovicells. For the purposes of the 

 formula, however, the ovicell is counted as an ordinary member of the inter- 

 node. A branch is probably never developed from the ovicell itself. 



