THE CIRRIPEDIA 



129 



proceed two ribboii-like tihiments (Fig. 79, A, md), Ijciiiitig at the 

 tip the larval aTitemiules, which agree in .structure, as already 

 noticed, with the type usual among normal Cirripedes. The six 

 following " segments " were regarded by Darwin as thoracic and 

 the three remaining as abdominal. All of them are devoid of 

 any trace of appendages. 



The alimentary canal is greatly reduced. According to Darwin, 

 only the oesophagus is ])resent, and there is no trace of stomacli, 

 rectum, or anus. The ovaries lie at the .sides of the anterior part 

 of the body and the testes posteriorly. The vasa deferentia unite 

 to open at the tip of the abdomen. There is no penis. 



KlQ. "'.'. 



Proteulepus Invinctc-. A, the entire animal ; ant, aiitennules ; B, buccal coue ; fiL'-e, ceniei.t- 

 j;laiicl ; p.p, penial papilla ; tes, testis ; v.s, seminal vesicle. B, dia^'ramniatic plan of nioutli- 

 ]iiiits ; ?.*•, upper lip; ind, mandible; mx, maxillula ; mx', maxilla. C, mandible and maxillula 

 separated ; m, muscle. (After Darwin, from Gruvel's Monogruphie.) 



"While I)arwin was unable to investigate the development of 

 the species, Hansen has recently conjecturally referred to the 

 Apoda certain nauplius larvae obtained in various parts of the 

 Atlantic Ocean and the Baltic, while more recently similar larvae 

 have been found in the Adriatic Sea. In late nauplius stages of 

 this type rudiments of paired compound eyes and of six pairs of 

 thoracic limits are visible, so that it can hardly be doubted that 

 they belong to some form of Cirripede. On the other hand, they 

 differ markedly in the absence of antero-lateral horns and of frontal 

 filaments, in the shape of the body, and especially of the strongly 

 developed dorsal shield, and in other characters from the known 

 Cirripede larvae, which, as already indicated, show great uniformity 



9 



