IV 



ri-:i>r\( i I.ATA < M'I:R< n.A t A 



89 



which they live ; they exliibit a degenerate structure, but still 

 retain two pairs of cirri. The large individuals of /. qutulrivalms, 

 on the other hand, are hermaphrodites, but they harbour within 

 their mantles minute complemental males similar to those of 

 /. cuminrfii, though they are rather larger. 



Fam. 4. Anaspidae. This includes the remaining pedun- 

 culate genera, characterised by the fleshy nature of the 

 mantle and peduncle, which are both entirely devoid of cal- 

 cifications. The species of Alepas live upon Echinoderms and 

 various other animals ; Chaetolepas upon Sertularia, and 

 Gymnolepas upon Medusae. Anelasma squalicola is an interesting 

 form, living parasitically upon the Elasmobranch fishes, >SV/m7/'- 

 i/iit.i-imii and Spinax niger in the North Sea. The peduncle is 

 deeply buried in the flesh of the host, so that only a portion of 

 the dark blue capitulum protrudes to the surface. From the 

 whole surface of the peduncle a system of branching processes is 

 given off, which ramify far into the tissues of the fish, and 

 communicate inside the peduncle with the lacunar tissue-, which 

 is packed round all the organs of the Cirripede. There can be 

 small doubt that the Anelasma derives its nutriment parasitically 

 through this root-system, since the cirri are mere fleshy lobes un- 

 adapted to securing food, and the alimentary canal is always 



empty. 

 gestive 



sug- 



derive 



system 



This animal has a 



bearing on the Ithizo- 



, which, as will be shown, 



their nutriment, from a 



of roots penet nil ing the 



R 



host, and growing out, from what, 

 corresponds morphologically to the 

 peduncle. 



Sub-Order 2. Operculata. 



B 



R.L 



C.L 



The "acorn-barnacles" appear 

 later in geological time than the 

 earlier stalked forms. I'm-in-n and 

 ( 'Itllm nntl HX are Found in the Chalk, 



FIG. 60. Diagram of tlic *lirll i MI, 



( >|iclvll!;ltl' I 'in i]lr,|r. ,1 " Al:l." "T 



overlapped \<i 1 MHI <>\' a ' i-i>m|i.irt 

 in, M| " : /,', lia-is : ' ', cariiiM : ' '. /.. 

 cariiiD-latiTal ; /.. lateral : /,'. 

 t ruin : r, " railius" T overlap 

 port inn nl' :> ci iini'Mi t meill : /!. /-, 

 rip-tni-]atfi';il. (After I ';" ill. i 



:ind survive down to the present 



day, but J lain im* does not occur until middle Tertiary times. 



Representatives of the last-named genus are familiar to every one. 



