154 Pub. Puget Sound Biol. Sta. Vol. 2, No. 44 



2. HISTORICAL 



The synnonomy of Salmincola edwardsii (Olsson) Wilson is rather 

 involved. The copepod was first studied by Mayor in 1824, who identified 

 it as Lernaeopoda salmonea, thus confusing the form with another species 

 of the same name which was first described by Gissler in 1751, and studied 

 by Linnaeus in 1761 and by Blainville in 1822. In 1840 Milne-Edwards 

 reclassified the species worked on by Mayor under the genus Basanistes, 

 and called it Basanistes salmonea. In 1868 Olsson proposed the name of 

 Lernaeopoda edzvardsii for the species under consideration, and showed 

 that it was a true member of the genus Lernaeopoda. In 1915 Wilson 

 established the new genus of the Salmincola and placed Lernaeopoda ed- 

 wardsii under it. Thus we have Salmincola edwardsii (Olsson) Wilson. 

 The synonomy of Salmincola edwardsii (Olsson) Wilson may be summar- 

 ized as follows: 



Lernaeopoda salmonea of Mayor in 1842. 



Basanistes salmonea of Milne-Edwards in 1840. 



Lernaeopoda edwardsii Olsson, 1868. 



3. MORPHOLOGY OF FIRST COPEPODID LARVA 



A. External anatomy 



The first copepodid larva (Fig 1) passes a free-swimming existence 

 in the water and is constantly hunting for a host to which to attach itself. 

 Since this larva has already been briefly described elsewhere (Fasten 1912, 

 1913), the description need not be repeated here. However, the append- 

 ages (Figs. 2 to 10) require more attention. 



The appendages are paired structures occupying the ventral surface 

 of the cephalon (Fig. 1, c) and the thoracic segments (Fig. 1 th). The 

 cephalon bears the first antennae (Fig 1, a'; Fig. 4), second antennae 

 (Fig. 5), mouth tube (Fig. 2), mandibles (Fig. 3), first (Fig. 6) and sec- 

 ond (Fig. 7) pairs of manillae, and the maxillipeds (Fig. 8). The first 

 and second thoracic segments bear, respectively, the first (Fig. 9) and sec- 

 ond (Fig. 10) pairs of swimming feet. 



The first antennae (Fig. 1, a'; Fig. 4; Fig. 23, a) are slender, uni- 

 romous structures consisting of four joints. The second of these joints 

 bears two long, straight setae, whereas the third joint bears a stout spine. 

 The fourth joint is somewhat thicker than the others and possesses eight 

 thin setae. 



The second antennae (Fig. 5 ; Fig. 23, a") are located a little below 

 the primary antennae. They are biramous appendages, bearing outer 

 exopods and inner endopods. Each exopod consists of a single joint that 

 terminates in two long spines. The endopod is three- jointed, consisting 



