12 



The coenoecium consists of a delicate tube, bifurcating from time to time, and enclosing a 

 cavity which is continuous throughout. Tlie orifiices, whicli appear to be confined to the ends 

 of the branches '), are funnel-shaped openings, with irregular margins, and they are produced 

 into a varying number of fine gelatinous "spines" or peristomial filaments. Similar filaments 

 occur in the more proximal parts of the tube, where orifices appear to have been occlucled 

 by the deposition of gelatinous lamellae. Thus at a in fig. 15 three embryos are contained 

 in a diverticulum of the main cavity which is completely closed distally, while the remains 

 of filaments probably indicate that this was once one of the functional orifices of the coenoe- 

 cium, when growth had not extended much beyond this point. Some parts of the tube 

 are completely empty, while others contain numerous embryos, as well as zooids (adult and 

 immature blastozooids), which are often so closely packed that it is difficult to tracé the limits 

 of the individuals. It is probable that the zooids, like those of C. dodecalophns, can wander at 

 will through the cavity of the coenoecium. But the long, Rkaddopletira-\\ke, stalk of this species 

 probably enables the zooid to reach an orifice while the base of its stalk is still deep in the 

 recesses of the coenoecium. 



The foreign inclusions in the jelly are small and inconspicuous, but they include a 

 considerable number of Diatoms and sponge-spicules. Many Diatoms are visible on the free 

 surface of the coenoecium, and some of these are probably, from time to time, included in 

 the jelly, in places where the deposition of fresh lamellae is taking place. It may be noted 

 that the inclusions commonly rest immediately on an older lamella, and are covered by the 

 next lamella. 



The structure of the coenoecium resembles that found in C. levinseni, thoug-h its law 

 of growth is much less definite than in that species. A consideration of fig. 16 will probably 

 give a correct idea of its mode of growth. The figure shews two orifices (a, b) and three 

 peristomial filaments [c, d, e). These filaments correspond with the "mid-ribs" of C. levviseni, 

 but are much more developed than in that species. They project far beyond the orifices as 

 cylindrical structures composed in the main of a series of overlapping conical primary lamellae, 

 the shape of which is not complicated by taking part in the formation of a tubular zooecium. 

 A few secondary lamellae, forming a transparent sheath to the process, occur in the more 

 proximal part. 



The tubular cavity of the coenoecium is being prolonged along these processes by the 

 development of oblique primary lamellae (shewn in the lower part of fig. 16), similar to those 

 of C. levinseni except in the fact that they take no share in the formation of the mid-rib, 

 which precedes their formation. As the tube of the coenoecium becomes prolonged along the 

 process, the mid-rib remains as a supporting rod passing along one wall of the tube. The 

 lamellae composing this rod usually become darker in colour with advancing age ; and as they 

 have taken no part in the formation of the lateral walls of the coenoecium, the cylindrical 

 supporting rod is sharply marked oft' from the rest of the coenoecium. 



i) Orifices ave present in fig. 15 at the points marlied by arrous. It is probable that others are really present as well; but 

 all the more proximal ones appear to have been closed. 



