434 



CRUSTACEA. 



present undergo further segmentation. Many parasitic Copepoda, 

 however, pass over the series of Nauplius forms, and the larva, as 

 soon as hatched, undergoes a moult, and appears at once in the 

 youngest Cyclops form, with antennas adapted for adhering and 

 mouth parts for piercing (fig. 344). From this stage they undergo 



a retrogressive metamorphosis, 

 in which they become attached 

 to a host, lose more or less com- 

 pletely the segmentation of the 

 liody which grows irregular 

 in shape, cast off their swim- 

 ming feet, and even lose the 

 eye, which was originally pre- 

 sent (Lernceopoda). The 

 males, however, in such cases 

 often remain small and 

 dwarfed, and adhere (fre- 

 quently more than one) firmly 

 to the body of the female in 

 the region of the genital open- 

 ing (fig. 345). 



In the Lernmi (fig. 346) 

 such pigmy males were for a 

 long time vainly sought for 

 upon the very peculiarly 

 shaped body of the large female 

 (fig. 346, c, d) which carries 

 egg tubes. At last it was 

 discovered that the small 

 cyclops-like males (fig. 346, ), 

 lead an independent life, and 

 swim about freely by means 

 of their four pairs of swim- 



mni a feet; and that the fe- 



. 

 males (fig. 436, 6), 111 



CO p U latory stage resemble the 



FIG. 345. The two sexual animals of Chandra. 

 tanlliUifjMoaHg magnified about six diameters. 

 a, Female seen from the side; 6, from the 

 ventral sin-face with adhering male ; c, male 

 strongly magnified. An', Anterior antenna?; 



srongy m. , . 



An", antenna? for attachment; F>, F, the males, and that it IS Only 



two pairs of feet; A, eye; On, egg-tubes; 

 Oe, oesophagus ; D, intestine ; M, mouth 

 parts ; T, testis ; Td, vas deferens ; Sp, 

 spermatophore. 



after copulation that they 

 (the females) become parasitic 

 and undergo the considerable 



increase in size and modification of form which characterises the 



female with egg-tubes. 



