210 



the lateral angles 

 of its frontal mar- 

 gin, is produced 

 out to form the 

 " frontal horns " 

 (h). The posterior 

 end of this dorsal 

 shell appears at 

 first to be rounded, 

 but at a later stage 

 may have a pair 

 of spines directed 

 backwards and 

 upwards. Each 

 of the frontal 

 horns contains a 

 style-like process 

 (Claus, No. 8), 

 while in the sheath 

 that covers this 

 are found the 

 openings of two 

 large and several 

 smaller unicellular 

 glands (Fig. 102 

 B, di\ Claus, No. 



8; WlLLEMOES- 



Suhm, No. 62). 

 This is probably 

 a protective appa- 

 ratus and not a 

 sensory organ. 

 The posterior end 

 of the body ( tho- 

 racoabdominal 

 section, Fig. 102 

 A,t) projects freely 

 out beyond the 



l ' i2.— Larval stages of Balanus (after Claus). A, older Nauplius stage. B, MetanaupUus. 

 " , llrst, a", second antenna; a/, anus; dr, glandular cells of the frontal horns ; da, dorsal 

 • ufidiil spine ; f*-fvi, first six pairs of thoracic limbs ; fs, frontal sensory organ ; h, frontal 

 boras; md, mandible; mx, rudiment of the maxilla; ol, upper lip: t, thoracoabdominal 



■ppmd ™ * ' ' 



