15 



The end of the tube is a widely open funnel (z), of which /c is the lower lip, and /, 

 m and ;/ are the peristomial filaments. 



The filaments have a structure similar to that found in C. gracilis^ consisting of a series 

 of overlapping cones, with an occasional, very delicate, secondary lamella on their outer side. 

 Some of the cones contain large numbers of minute granules, which are indicated in the upper 

 part of the principal process n. Similar granules may occur in smaller numbers in the lateral 

 lamellae. 



It need hardly be pointed out that when the peristomial filaments become included in 

 the wall of the tube, they retain the structure which they have at their first formation. The 

 series of primary cones may thus be traced throughout the supporting sheletal bars which result 

 from the modification of the peristomial filaments. 



Secondary lamellae are not much developed in the erect tubes of C. sibogae, though a 

 certain number occur on the outer side of the wall, and are probably in many cases responsible 

 for taking up the foreign inclusions which form so conspicuous a feature of the species. The 

 basal parts of the tubes may be lined by several layers of internal secondary lamellae. 



The basal encrustation is a continuous film, with a smooth glistening surface, free from 

 foreign inclusions. It moulds itself over all the irregularities of the stone on which the specimen 

 is growing, and it is traversed by a continuous set of irregular cavities which contain the deeply 

 pigmented zooids. The layer in actual contact with the stone is quite thin. A section of a part 

 of the basal encrustation is shewn in fig. 102, and a part of the same figure, more highly 

 magnified, to illustrate the details of the lamination, in fig. 103. The tube a is cut longitudinally, 

 and shews on either side a well marked series of primary cones (rt', e\ of which the series d 

 has given off a lateral branch, ƒ, which has the same structure. In the interval between ƒ and 

 the upper part oi d -a. few secondary lamellae can be recognized, while a certain number of 

 similar lamellae line the cavities of the tubes. It should be noted, however, that some of the 

 lamellae to the left of d are really primary lamellae cut tangentially. 



It cannot be denied that the coenoecium of C. sibogae resembles that of C. gracilis in 

 some respects; but the differences between the two specimens seem to be sufficiënt to indicate 

 that they belong to distinct species, even making full allowance for the fact that they are of 

 different sexes. 



C. dodecalophtis. (PI. II, figs. 20, 21). 



The general characters of the coenoecium are well illustrated by M'Intosh (87, text-fig. 

 on p. 4, PI. I, PI. MI, fig. i). Although offering an obvious generic similarity to that of 

 C. levinseni, the coenoecium of C. dodecalophus differs from it in several noteworthy points. 

 Instead of having a separate cavity for each zooid, it resembles that of C. gracilis and C. sibogae 

 in containing an irregular, continuous, axial cavity, some parts of which may be empty, while 

 others are crowded with zooids and eggs. The cavity communicates with the exterior by rounded 

 orifices which are not borne by jarominent peristomes (fig. 21). 6". dodecalophus is characterised 



