DESCRIPTION OF PLATE, 24. GG1 



Fig. 14. Segments of one of the rami much enlarged; «, thickened 

 shield-like portion of membrane. 



15. Ovum, (thirty-five times the natural size.) 



16. Egg-like larva in the first stage, on same scale. 



17. „ „ in the second stage, on same scale. 



18. Larva in the last or pupal stage, on four times the scale of 



fig. 15 — 17; a, antennae; b, apodeme and eyes; c, ab- 

 dominal bristles. A male would have been developed from 

 this pupa. 



19. Male on same scale as the pupa, fig. 18 ; a, three terminal 



segments of the antennae of the pupa ; d, orifice of the 

 sack. 



Proteolepas bivincta. 



Fig. 1, Antenna of the pupa (three terminal segments of), with a portion 

 of one of the two threads, enclosing the cement-ducts, by 

 which the body of the Proteolepas is attached ; the upper 

 portion of the thread, and the adjoining part of the body, 

 are represented in section. 



a, part of the great mass of cellular matter within the ovarian 



sack, in process of development into ova, and changing 

 its character as soon as it enters the tube or cement-duct. 



b, membrane forming the ovarian sack and the cement-ducts, 



the latter euclosed within the threads of attachment. 



c, corium lining the outer membrane of the body, and the upper 



part of the threads. 



d, outer membrane of body. 



e, ,, ,, becoming suddenly thicker where 

 forming the outer membrane of the thread. 



e', outer membrane of the thread in the lower part, here not 

 shown in section. 



f, main or second segment of the pupal antenna, the basal seg- 

 ment having, as in all cases, been moulted, with the cara- 

 pace of the pupa. 



ff, disc-segment, apparently with a small orifice for the issuing 

 of the cement. 



h, terminal segment with the shorter spines broken off, 



2, Compounded mandibular organ, sketched by the camera , a, 



supposed mandible ; b, perhaps portion of the mandible ; 

 c, maxilla; d, ligamentous fibres giving attachment to 

 muscles. 



3, Mouth seen from the ventral side, sketched by the camera ; r, 



articulation separating the mouth from the body ; c, com- 

 pounded mandibular organ : d, palpus, united to the op- 

 posite palpus and to the crest of the labrum ; the latter 

 forming' the back of the hollow in which the compound 

 mandibles work. 



4, Diagram of the mouth of an ordinary cirripede, seen from 



above ; a, outer maxilla ; b, maxilla ; c, mandible ; d, 

 labrum. 



