PLATE IX. 



Figs. 95 — 99, 102, 103. — C. sibogae. 

 Figs. 100, lOi, 104 — 1 10. — C. lei'inseni. 



Fig. 95, 96. C. sibogae. — Two views (Zeiss, C) of the anterior part of the male shewn in I'l. \'II, fig. 76. 

 Pig, c)5. — Anterior view. The ventral lobe (/'.) of the proboscis is turned forwards, exposing the mouth 



(w.), on each side of which is seen a collar-canal [c.c). The mouth leads to a vestigial alimentary 



canal, the intestinal limb of which is marked r. R.a. and L.a., right and left arms; t.r.,t.L, 



right and left testes. 

 Fig. 96. — Posterior view of the same specimen: — c.n.s., swelling of collar due to the presence of the 



central nervous system; g.p. appears to be one of the generative pores; d.v., dorsal vessel; 



r., intestinal limb of alimentary canal. 

 Fi". 97. C. sibogae. — Frontal section of anterior end of the specimen shewn in PL \'I1I, fig. 92, shewing 



the proboscis (/.), and the four pairs of arms (ZEISS, C). 

 Fif. 98. C. sibogae. — Abnormal arm of a tentaculiferous individual, the distal end of which is produced 



into a long vesicle-bearing portion, resembling the arm of a male (ZEISS, C). The arm may 



belong to the first pair, but this is uncertain. The individual to which this arm belongs appears 



to have a pair of testes, in the position of the ovaries of a female Ceplialodiscns. The testes, 



though small, seem to be functional. The specimen in other respects resembles a normal neuter: — ■ 



tent., tentacles. 

 Ficr. 99. C. sibogae. — Base of arm of a young male, partly in optical section, shewing the characteristic 



epidermic vesicles, which do not occur in the pro.ximal region of the arm (Zeiss, D D). 

 Fig. 100. C. levinseni. — Obliquely sagittal section of a young individual (ZEISS, C). The proboscis-stalk 



is strongly contracted and bent, as is indicated by the fold (/.) of its dorsal body-wall: — 



«.', one of the first arms. 

 Fie. loi. C. levinseni. — Lateral sagittal section of an old individual with reversed proboscis (ZEISS, C): — 



/.,/., folds of body-wall of proboscis which appear to indicate the region where the rotation 



has been effected. 

 Fio'. 102. C. sibogae. — Section of part of the basal encrustation of the coenoecium (Greenougm bino- 

 cular, a-.). The letters indicate the corresponding parts in fig. 103. 

 Fi<T. 103. C. sibogae. — Part of fig. 102, more highly magnified (ZEISS, A). For explanation of lettering, 



see text, p. 15; ^^ a secondary lamella. 

 Figs. 104 — 106. C. levinseni. — Sagittal sections of an embryo (ZEISS, C). 

 Fig. 104. — Lateral section, shewing the dorsal vacuolated ectoderm {vac), the ventral thickening {v. t.) 



and the three body-cavities {b. f.'"''). 

 ?\o. 105. — Nearer the middle line: — the yolk-mass (yk) is divided into three portions. 

 Fjcr. 106. - — More median region: — s.o., sense-organ (?), which appears as an invagination of the vacuo- 



lated ectoderm [vac). The two principal divisions of the yolk-mass are less clearly seen here 



than in some of the figures on PI. XIV: (Ui. is probably the future anus: b.c.'- is visible on the 



dorsal side of the yolk-mass. 

 Fi". 107. C. levinseni. — Transverse section through the ventral border of the collar and jiart of the 



metasome (Zeiss, D D). The operculum (op.) is directed forwards, and appears emarginate in the 



middle line: — v.ntes."^, ventral mesentery of collar; v.mes.'^. of metasome; s.-j^, trunco-collar 



septum; III., level of mouth; b.in., basement-membrane of oral epidermis of operculum, with muscles. 

 Fif'. 108. C. levinseni. — Transverse section of a peristome (Zeiss, A): — w. ;-., mid-rib; pr.l., primary 



lamellae. 

 Fi". 109. C. levinseni. — Transverse section through an entire branch of the coenoecium (GreENOUGH 



binocular, a.^). The letters indicate the corresponding parts in fig. no. 

 Fig. I 10. C. levinseni. — Part of fig. 109, more highly magnified (ZEISS, A): d, e, f, cavities of zooecia; 



pr.l., primary lamellae. For other letters, see text, p. 10. 



\All the figures have been reduced ^/,]. 



