PLATE I. 



Figs. I, 4, 7, 8, 9. — Ceplialodiscus gracilis. 

 Figs. 2, 3. — C. sibogae. 

 Figs. 5, 6, 10. ■ — • C. levinseni. 



Fig. I. C. gracilis, • i. — The left hand portion of the figure shews a portion of the colony, detached 

 from the substratum; its transparent coenoecium containing masses of orange-coloured zooids. The 

 right hand portion shews another part of the coenoecium, inckiding but few zooids, growing on 

 a species of TubuccUaria (probably T. fusiforinis D"Orb.). 



Fig. 2. C. sibogae, :% i. — Shewing the erect, orange-coloured tubes of the coenoecium, originating from 

 a basai encrustation on a stone. The dark masses seen in the tubes to the left of the figure are 

 zooids, most of which are, however, retracted into the basal encrustation, which owes its dark 

 colour to the zooids contained therein. The colour of the stone has not been indicated. 



Fig. 3. C. sibogae. — Anterior view of a neuter individual. Of the five arms seen on the right side of the 

 drawing, the most posterior belongs to the right side, while the others are the four left arms. 

 One of the right arms is marked R. a., but the details cannot be made out in the preparation. 

 The only part of the operculum which can be distinctly seen is that marked op. l. 



Fig. 4. C. gracilis. — Group of buds. Two budding systems, marked respectively ^ and i?, are intermingled: 

 the numbering indicates the approximate relative ages of the individuals. The system A consists 

 of four degenerated stalks [A. i — ^) and a single bud [A. s), which has two arms (not drawn). 

 The system B consists of a basal disc [d.], belonging to the degenerated stalk B. i : B. 2, j are 

 degenerated stalks: B.//. shews five right arms and three left arms: B. j is seen in anterior view, 

 two arms (not shewn) being moderately well developed on its right side : B. 6 has a single pair 

 of arms, indicated as spherical knobs: B.J has just differentiated its proboscis. 



Fig. 5. C. levinseni. — Young zooid. The complicated fold of the anterior surface of the proboscis is 

 represented with only partial success. The stalk (st.), which is much like that of C. dodecalopJius, 

 is overlapped by the proboscis : — a, mass of arms and tentacles. 



Fig. 6. C. levinseni. — Side view of an older zooid. The proboscis is in the reversed position which it 

 frequently assumes in this species, as is indicated by the position of the pigment-band (/. b.). 



Fig. 7. C. gracilis. — Side view of adult zooid. 



Fig. 8. C. gracilis. — Posterior view of a young bud with a single pair of arms [a.]. The pigment-band 

 of the proboscis is already developed, and is seen through the metasome (niet.), while the collar (<:) 

 is marked oft" from the metasome by a slight dorsal groeve. 



Fig. 9. C. gracilis. — Anterior view of an older bud, from the same budding system as fig. 8. The arms 

 are seen through the proboscis. The young posterior arms are seen at the base of the two well 

 developed arms on the left of the figure. 



Fig. 10. C. levinseni. — • Part of the coenoecium, X i, represented in its natural colour. Someofthe elongated 

 zooids are visible in the cavities of the zooecia. 



\Figs. I, 2 and 10, drawn by Mr. E. WiLSON, are of the natural size. The reinainiiig Jigitres were drawn 

 ivith ZeiSS, A Obj. and have not been rediiced]. 



