EXPLANATION OF PLATE V. 



Figs 1 to 8, Cirripedia. 



Fig. 1. Sacculina carcini (Thomps.) seen in plan, showing by 

 means of the dotted outline of the crab upon which it is 

 parasitic, the manner in which the root- tubules ramify 

 through the host's body. Natural size. 

 b.s. body-sac of Sacculina ; cL cloacal opening ; b.m. basilar 

 membrane ; i.r. the roots which ramify around the 

 intestine and the associated organs ; h.r. hepatic roots 

 ramifying among the caeca of the liver ; br.c. branchial 

 cavity of the host. 



Fig. 2. Lateral view of same. 



Fig. 3. Life appearance of Rock Barnacle (B. balanoides), enlarged. 



Fig. 4. The same seen from above, , 6, c, d, e, and /, the six 

 plates making up the circular mantle " rampart." 



Fig. 5. Dissection (partly diagrammatic) of B. balanoides , the right 

 half of the mantle-wall removed ; the " liver," cement 

 gland, and branchiae are omitted ; the alimentary canal 

 is depicted black ; for clearness, the male organs are not 

 lettered, but reference to Fig. 7 will indicate their parts. 



Fig. 6. A Ship-Barnacle (Lepas) having the right side of the mantle 

 removed. The penis should not be apparent, as it lies 

 normally folded up between the cirri. 



Fig. 7. Dissection of same, on the lines of Fig. 5. 



Fig. 8. External appearance of Lepas anatifera, natural size. 



Lettering the same for all the figures : a remains of the 



anterior antennae ; an. anus ; a.m. adductor muscle ; c. carina ; 



c.f. caudal forks ; e.g. cement gland ; cr. cirriform feet ; c.s. calcareous 



rampart-shell of mantle ; f.a. filiform appendages of 1st pair of feet ; 



h. liver ; I. labrum ; m retractor muscle of scutum : m" retractor 



muscle of tergum ; m.c. mantle cavity ; od. oviduct ; or.c. buccal 



eminence ; o. mouth ; ov. ovary ; p. penis ; pd. peduncle or stalk ; 



s. scutum ; t. tergum ; ts. testis ; v.d. vas deferens ; v.s. seminal 



vesicle. 



Figs A to D, Plumularia pumila. 



Fig. A. Branches of P. pumila, slightly larger than life. g. gonangia ; 



8. creeping stem or stolon connecting the various bundles. 

 Fig. B. Portion of branch, highly magnified, hydranths or polypites 



in various stages of extension ; k. body of the hydranth ; 



Jd. hydrotheca lodging hydranth ; g.c. gastric cavity of 



hydranth ; c. coenosarc ; c.c. cavity of the coenosarcal tube ; 



pr. perisarc ; z. tissue connecting hydranth with lateral 



and internal surface of hydrotheca ; ec. ectoderm ; en. 



endoderm ; d.hc. developing hydrocaulus or stem ; d.h. 



developing hydranth. 

 Fig. C. Female gonangium ; bl. blastostyle ; c. swollen hollow apex 



of blastostyle nearly ready to force its way through the 



mouth of the gonangium ; ov. ova. 

 Fig. D. The same fully developed, showing the acrocyst containing 



ova. (After Lindstrom). 



