160 Pub. Piiget Sound Biol. Sta. Vol. 2, No. 44 



end of the filament. Degeneration soon sets in and the organism changes 

 considerably. The female copepod remains thus attached throughout 

 life, while the male remains attached in this way until shortly before it is 

 mature for copulation." Since the above statements, the author has made 

 a very careful study of his numerous preparations and has discovered 

 news facts, which clear up many of the obscure points regarding the at- 

 tachment, as well as the later attached stages of the organism. 



One of the things which could not be pointed out was the apparatus 

 that was responsible for the discharge of the attachment filament from the 

 cephalon of the copepod into the tissues of the host. The discovery of the 

 thin muscles (Figs. 24 and 25, ft. m) connected with the foot of the at- 

 tachment filament clarifies this obscurity. The contraction of these mus- 

 cle strands causes the injection of the bulla into the flesh of the host. Fig- 

 ure 22 shows the head region of the first copepodid larva in contact with 

 a portion of the gill, prior to attachment. Note how the second maxillae 

 (Fig, 22, mx") rasp the tissue of the gill (Fig. 22, g). Figure 23 is a draw- 

 ing of the organism immediately after the injection of the bulla into the 

 gill tissue. Here the animal is seen attached at the frontal margin (Fig. 



23, f. m) to the foot (Fig. 23, ft) of the attachment filament. When the 

 attached region between the foot and the frontal margin is examined un- 

 der the high powers of the miscroscope the contracted foot muscles (Fig. 



24, ft.m) can be seen quite plainly. 



Another point which can now be cleared up, is the question of the 

 permanent attachment of the organism. Wilson (1911, 1915) and the 

 present writer (Fasten, 1913) came to virtually the same conclusion re- 

 garding this point; namely, that the maxillary attachment of the copepod 

 serves as the final and permanent attachment for the female, while for 

 the male it serves as a temporary attachment, until he is ready to seek 

 out a female for copulation. However, a careful study of the copepod 

 in all stages of attachment has led the writer to the conclusion that prior 

 to sexual maturity, the maxillary attachment is quite as temporary for 

 the female as it is for the male. The permanent attachment of the female 

 takes place about the time when she is mature for fertilization. In order 

 to get a comprehensive idea of these stages, it will be necessary to trace 

 briefly the changes which occur in the first copepodid larva from the time 

 of its initial attachment until it becomes sexually mature. 



As already pointed out in the above citation,, the larva hangs on for 

 a short j^eriod at the frontal margin. Soon the second maxillae detach the 

 proximal or foot end of the attachment tube from the frontal margin, and 

 then their powerful claws are driven into this detached foot. Figure 26 

 shows the claws of the second maxillae (mx") immediately after being 

 driven into the foot (ft) of the tube of attachment (t). Degeneration 



