Ill 



PODOPLEA AMPHARTHRANDRIA 



Ascidiella scabra at Concarneau), in which the female has lost 

 its segmentation, the mouth-parts and thoracic legs being purely 

 prehensile, and various species of Enterocola, parasitic in the 

 stomach of Compound Ascidians, in which the female is a mere 

 sac incapable of free motion, while the male preserves its swim- 

 ming powers and a general Cyclops-form (Fig. 34). We 



Ant!, 



FIG. 34. Enterocola fidyens. A, Ventral view 

 of ? , x 35 ; B, side view of <J , x 106. 

 .\bd.l, 1st abdominal segment ; Ant.l, Ant.2, 

 1st and 2nd antennae ; c.m, gland-cells ; n, 

 ventral nerve-cord ; og, ovidncal gland ; ov, ovary ; 

 pit, vagina ; Th.l, 1st thoracic appendage ; Th./t, 

 Th.5, 4th and 5th thoracic segments. (Aftt-r 

 Cauu.) 



FIG. 35. Asterocheres violaceus, ? , 

 with egg - sacs, x 57. (After 

 Giesbrecht.) 



have here the first instance of the remarkable parallelism between 

 the degree of parasitism and the degree of sexual dimorphism, a 

 parallelism which holds with great regularity among the Cope- 

 poda, and can be also extended to other classes of parasitic animals. 

 Fam. 6. Aster ocheridae. 1 These forms retain the power of 

 swimming actively, and are very little modified in outward 

 appearance by their parasitic mode of life (Fig. 35), though they 



1 Giesbrecht, Fauna and Flora G. v. Neapel, Monogr. 25, 1899. 



