PODOPLEA AMPHARTHRANDRIA 



67 



Ascidiella scahra 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-iorm (Fig. 34). We 



Fig. 34. — Entewcola fuUjens. A, Veutral view 

 of 9, X 35; B, side view of J , x 106. 

 Abd.l, Ist abdominal segment ; AiU.l, Ant.'£, 

 1st and 2nd antennae ; c.jk, gland-cells ; »i, 

 ventral nerve-cord ; ofj, oviducal gland ; oc, ovary ; 

 pi), vagina ; Th.l, 1st thoracic appendage ; T/1.4, 

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

 Canu. ) 



Fig. 35. — Asterocheres violaceus, 9 , 

 with egg -sacs, x 57. (Alter 

 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 witli great regularity among the Cope- 

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

 Fam. 6. Asterocheridae.^ — 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 



^ Giesbrecht, Fauna and Flora G. v. Ncapel, Monogr. 25, 1899. 



