26 ME. A. W. WATERS ON THE MARINE 



made unnecessarily puzzling by the use of the plus ( + ) sign, where plus is 



not really meant, for the number of zooecia in a brunch is first given, then 



where a new branch occurs is indicated, but this is not a plus, it is not 



additional, unless the subbranching zooecia are first mentioned separately ; 



and by putting a comma instead of the + the disconcerting "algebroide" 



appearance is done away with. We thus give the number of zooecia, say 9, 



and show that the new branch occurs after the second zooecia, and whether 



the branch is on the right or the left by the position of r. There is, of course, 



not the objection to brackets that there is to the plus, but it is more easily 



printed with a colon. A specimen from the Cape Verde Island collection 



reads : — 



9, r 2 : 9, 2 r : 12, 2 r, x . 



18, i»-, or 3 , r ,r, r 4 , X . 



12, r r, or 8 , x . 



This is a piece near the growing end, whereas at the base there are a 

 number of internodes without zooecia, or very few, before the typical inter- 

 nodes are formed. The example formula only deals with three branches, 

 while many colonies will have fifty, and for some colonies a large sheet of 

 paper is required, though the main features of a hundred colonies might 

 sometimes be given in a few lines. It should be noticed that the growing 

 branch frequently contains a larger number of zooecia than other branches. 

 A further complication in the formula occurs in Harmer's last paper, a brunch 

 on the right has r and a small figure below, whereas a branch on the left has 

 a large figure and a small r above, but, although it occurs throughout, it must 

 surely be a printer's error. 



In giving the measurements of the distance from zooecia to zooecia it, of 

 course, must not be supposed that there is no variation, but if mature branches 

 are taken, though not the lower zooecia on a branch, then it will usually be 

 found that the variation from the average is but slight. 



Crisia tubulosa, Busk. (Plate 3. fig. 1.) 



Crista tubulosa, Busk, Cat. Mar. Polyzoa, pt. iii. p. 7, pi. vi. A. figs. 3, 4 (1875). 



In the Boa Vista specimens the zooecial tubes expand at the end, the 

 aperture measures about 0"12 mm., which is a trifle smaller than the British 

 Museum specimen, and the zooecial tube is free for a considerable extent. 

 The ends of the zooecia are 0'5 mm. apart, and except in the lower internodes 

 there are more zooecia than given by Busk, sometimes as many as 16. The 

 branches arise from the second, third, or fourth pairs. The ovicells are elongate 



