CIRRTPEDIA. 413 



Reproduction. The males are smaller and more agile than 

 the females. The paired testes lie in the two lobes of the 

 abdomen and the vasa efferentia lead to a median vesicula 

 seminalis from which paired ducts pass to the median genital 

 papilla at the base of the abdomen. Fertilization is effected by 

 means of seminal sacs which are situated at the distal ends of 

 the basal segments of the third pair of swimming feet, an 

 arrangement recalling those found in spiders and cephalopods. 

 Copulatory hooks are placed in a corresponding position on the 

 fourth pair. The oviduct leading from the median ovary opens 

 at the base of the abdomen. The females do not carry their 

 eggs about in sacs in the typical copepod manner, but fasten 

 them to surrounding objects. The vitelline membrane of the 

 deposited eggs acquires a vesicular structure. The young 

 when hatched have the general form of the adult, but the 

 appendages, as shown by Claus, resemble those of later copepod 

 larvae. They undergo a metamorphosis. 



Fain. Argulidae, Carp-lice. Argulus O. Fr. Mull. The anterior pair of 

 maxillipeds modified into large suckers. There is a styliform spine 

 in front of the mouth. A. foliaceus L. (Poudepoissons, Baldiier) parasitic 

 on carp and sticklebacks. A. coregoni Thor., A. giganteus Luc., Dolops 

 Aud. (= Gyropeltis Hell.). The maxillipeds end in a claw; stylliform 

 spine absent. D. Kollari Hell., parasitic on the branchiae of Hydrocyon, 

 Brazil. D. Doradis Corn. Chonopeltis Thiele. 



Order 5. CIRRIPEDIA.* 



Fixed, and for the most part hermaphrodite Crustacea with 

 indistinctly segmented body enclosed by a dorsal shield (mantle] 

 which generally contains calcareous shell plates. As a rule there 

 are six pairs of biramous thoracic appendages. A remarkable 

 change in the position of the body within the shell occurs in most 

 cases during the metamorphosis. 



* Compare J. V. Thompson, Zoological Researches, vol. 1, 1829. H. 

 Burmeister, Beitrage zur Naturgeschichte der Rank en fussier, 1832. Ch. 

 Darwin, A monograph of the Sub-Class Cirri pedia, 2 vols., London, 1851- 

 185 1. A. Krohn, Die Entwickelung der Cirripedien, Archiv. fur Natur- 

 gesch., 1860. C. Claus, Die Cypris-ahnliche Larve der Cirripedien, etc., 

 Schriften Ges. Naturw. Marburg, Suppl. Heft. V. 1869. R. Kossman, Sttc- 

 toria und Lepadina, Wiirzburg, 1873. Yves Delage, Evolution de la 

 Sacculine, Arch, de Zool. exp., (2), II., 1884. Hoek, Report on the Cirri- 

 pedia, Challenger Reports VIII (1883) and X (1884). Berndt, Zur Biologic 

 u. Anatomie v. Alcippe larnpas Hancock. Z. f. w. Z., 74 (1903), p. 396. 

 Gruvel, A., Monographic des Cirrhipedes, Paris, 1905. G. Smith, Rhizo- 

 cephala, Fauna u. Flora d. Golfes von Neapel, Monograph 29, 1906. 



