162 Pub. Puget Somid Biol. Sta. Vol. 2, No. 44 



This last named structure instead of bearing a single claw as it did in 

 the free-living larvae (Fig. 8), now bears two claws (Figs. 28, 29 and 81, 

 mxp; 32 and 33). The maxillipeds thus come to resemble chela with 

 inner and outer claws. In the maxilliped of the female copepod (Fig. 



32) the inner claw is curved into a pronounced hook, while the outer claw 

 is straight and spine-like. In the maxilliped of the male copepod (Fig. 



33) both the claws are slightly bent, but they are not nearly as promi- 

 nently developed as in the female. 



Very shortly before the copepods reach full sexual maturity (between 

 two and three weeks after attachment) the maxillipeds function as aids in 

 the permanent attachment of the organism. The male releases his maxil- 

 lary hold on the attachment filament, and by means of the maxillipeds at- 

 taches himself to the abdomen of a mature female for copulation. For a 

 fuller discussion of the attachment of the male to the female see Fasten, 

 1914. 



In the case of the female, the maxillipeds (Figs. 28, 29 and 31, 

 mxp) first work their way upward into the open space lying between the 

 second maxillae (Figs. 28, 29 and 31, mx"), and then by means of the 

 powerful claws they grasp the flesh of the gill (Fig. 31, mxp and g), 

 thereby bringing the organism closer to the gill proper. As soon as the 

 copepod is thus securely fastened, the second maxillae (Fig. 31, mx") 

 withdraw their claws from the proximal foot of the attachment tube (Fig. 

 31, t), and begin a sort of creeping process along this last named struc- 

 ture, until they reach the posterior region of the chitinized bulla implanted 

 in the gill tissue. Here the claws of the second maxillae are securely 

 driven in and the female becomes permanently attached for the rest of her 

 life. The maxillipeds are soon withdrawn from the gill and undergo de- 

 generation (compare Figs. 32 and 36). The second maxillae elongate, be- 

 come intensely muscular and assume their adult appearance (Figs. 34 and 

 35, mx"). The tube of the attachment filament soon shrivels up and dis- 

 integrates, while the bulla transforms into a chitinized, funnel-shaped 

 structure (Figs. 34 and 35, bu). 



From the above discussion it is evident that there are three stages 

 of attachment: (1), the initial stage, when the frontal margin of the or- 

 ganism is fastened to the foot of the attachment filament; (2), when the 

 copepod is attached by its second maxillae to the foot of the attachment 

 filament; (3), when the copepod becomes attached as an adult, either the 

 male to the female, or the female to the chitinized bulla. The first two 

 stages of attachment are temporary, while the third is permanent. 



The investigators who have concerned themselves with the Lernae- 

 opodidae, such as Claus (1862), Vejdovsky (1877) and Wilson (1911 and 

 1915), claim that when once the female larva has attached the second 



