f>64 



ZOOLOGY 



SECT. 



support ; these are the antennules, and their position relatively to 

 the mandibles shows that the stalk is formed by an elongation of 

 the anterior region of the head. 



l- 



B 



a' 



FIG. 461. Lepas anatifera. A, the entire animal ; B, anatomy. a\, autennule ; c. car-inn: 

 cd. cement-gland ; 1. digestive gland ; m. adductor muscle ; od. oviduct ; ov. ovary ; p. .(in ) 

 penis and (in A) peduncle ; s. scutum; t. tergum and testis ; vd. vas deferens. (From 

 Lang's Comparative Anatomy, after Darwin and Claus.) 



The Sessile Barnacles or Acorn-shells (Balanus) have no stalk 

 (Fig. 462), the head-region being short and broad. The scuta (s) 



ad, 



4 



QD WQ 



Flo. 4C2. Balanus. A, external view ; B, anatomy, oj. antennules ; ail. adductor muscle ; 

 m. muscles of scuta and terga ; o. edge of parapet ; ov. ovary ; on. oviduct ; *-. scutum ; 

 sk. parapet; t. tergum; wo. female aperture. (From Lang's Compuratii-f . I imt<> ///.//, alter 

 Darwin.) 



