138 SIDNEY F. HAEMEB. 



diameter is about '45 mm. Mr. Kirkpatrick further informs me that 

 the distance from aperture to aperture is '4 mm., and that the total 

 length of the zooecium is about "7 mm. Although these numbers are 

 distinctly smaller than the average measurements of corresponding 

 structures in C. ramosa, I am inclined to believe that my own 

 specimens belong to the same species as the one in the British Museum. 



Waters (25), in 'Ann. and Mag. Nat. Hist.,' 5 sen, vol. iii, 1879, 

 p. 269, pi. xxiii, fig. 4 (" Bryozoa of the Bay of Naples"), identifies 

 C. fistulosa, Busk, with what he calls C. elongata, var. angustata. 

 I cannot, however, believe that C. ramosa is identical with the form 

 described by Waters. Although the number of zocecia iu the internode 

 in C. ramosa may be large, this species could hardly be characterised 

 as having fourteen to twenty-six zooecia in the internode ; nor does 

 the description, " branches arising usually from the fifth to eighth 

 zocEcium of a branch, and at about the same distance a fresh branch 

 grows on the other side," correspond with the branching of C. ramosa. 

 As Mr. Kirkpatrick has pointed out to me, Waters' statement that 

 the zooecia are '04 mm. apart was no doubt due to an oversight. 



For further remarks on C. fistulosa, Busk, see Vine (19), p. 589. 



The characters of the ovicell are so constant in my specimens 

 that, taken in conjunction with other facts, I cannot resist the 

 conclusion that this form deserves recognition as a species. 

 Although it is obviously alluded to in some of the works just 

 quoted, I cannot identify it with certainty with any form which 

 has hitherto received a specific name ; and I therefore suggest 

 for it the name C. ramosa, in allusion to the large number 

 of the branches given off by a single internode. 



C. ramosa has been found in large numbers at Plymouth, 

 where it is certainly the commonest of all the forms of Crisia. 



While the identification of fully developed colonies of Crisia 

 — in those cases at least where ovicells are present — cannot often 

 be a matter of doubt, it may be extremely difficult to identify 

 the species to which a small fragment of a colony or a young 

 zoarium belongs. The greatest difficulty is found, in these 

 cases, in distinguishing C. eburnea from C. aculeata, or 

 the latter species from C. ramosa. The characters of the 

 several species can be best brought out by a careful comparison, 

 under a series of distinct heads, of their more obvious external 

 features. 



