ON THE BRITISH SPECIES OF CRISTA. 135 



zooecium next below it on the same side^ unless it is borne by 

 the lowest zooecium of an internode. Zooecia usually with a 

 long, free, tubular portion bearing the aperture ; this portion is 

 distinctly curved forwards, but is usually lost in the older parts 

 of the colony ; in other cases this tubular portion is not 

 developed to more than a very slight extent. Aperture circular, 

 without any pointed projection on its outer side. O vie ell 

 very large, and more regularly pear-shaped than in any of the 

 other species; usually a little higher in the internode than in 

 C. aculeata, but in some cases it may occupy as low a position 

 as that of the fourth member of the internode ; it is perhaps 

 most commonly in the position of the 6th — 8th member ; its 

 aperture circular, borne on a long and very conspicuous 

 funnel-shaped tube, which is considerably wider at its summit 

 than at its base. Uootlets often developed in considerable 

 numbers, sometimes attaining a great length (nearly an inch), 

 and composed, for the most part, of long segments, separated by 

 yellow or colourless joints. (See also measurements on p. 177.) 

 (The following list includes references to several forms of 

 Crisia which, as explained below, I do not believe to be 

 identical with C. ramosa.) 



? C, cribraria. — 



(21) Stimpson. — " Synopsis of the Marine Invertebrata of Grand Manan 



[Bay of Fundy]," * Smithsonian Conts. to Knowledge,' vol. vi, 



1854. 

 This species may be identical with C. ramosa, in which case my 

 own specific name will have to be given up. The zocecia are described 

 as being " so crowded as to form often two or three longitudinal rows, 

 in which they are usually opposite " (p. 18). I do not see how such 

 a statement could be made of C. ramosa. The figures given (pi. i, 

 figs. Sa — c), although not unlike that species, are not drawn with 

 sufficient care to enable a satisfactory conclusion to be arrived at. 

 ? C. arctica. — 



(22) M. Sars. — " Geol. og Zool. Jagtt. anst. p. en Reise Trondiijems 



Stift.," Christiania, 1863. 



The zoarium of this form is said to reach the height of 30 mm. ; 



the branches and the zocecia are straight, or nearly straight; the inter- 



node possesses, on each side, two to three, often eight to twelve, rarely 



twenty to twenty-one zocecia. The species is said to resemble C, 



