of the Fishery Board for Scotland. 



199 



slender and two-jointed — both branches strongly setiferous. The maxilla? 

 are very similar to those of the Calanidce (fig. 5). Anterior foot-jaws 

 furnished with several marginal setiferous processes ; the last process 

 armed with a strong spine in addition to three aculeate setae ; terminal 

 joints small, furnished with a number of slender setae. Posterior foot- 

 jaws somewhat rudimentary, bearing numerous marginal and delicate 

 plumose setae. A long delicately plumose hair springs from the lateral 

 aspect and near the base of the foot-jaw, and a few similar hairs from 

 near the middle and distal extremity (fig. 7). The first pair of swimming 

 feet are comparatively short ; both branches are of about equal length, 

 and composed of three sub-equal joints. The second joint of the outer 

 branch bears a long, curved, spiniform, and blunt-pointed marginal seta. 

 The last joint is armed with three spiniform marginal setse, but these are 

 considerably shorter than that on the second joint ; both branches other- 

 wise more or less setiferous. The second pair of swimming feet have the 

 inner branches greatly elongated — being equal to about three times the 

 length of the outer branches (the third joint alone is nearly equal to twice 

 the length of the outer branch). The end of the outer branch extends to 

 a little beyond the second joint of the inner one. The long joint of the 

 inner branch is armed on the outer aspect and near the middle — but 

 nearer the proximal than the distal end — with a large aculeate spine, and 

 with two similar but smaller spines on the inner aspect — one near the 

 middle of the joint, but posterior to the large outer spine, and one about 

 one-fourth of the length of the joint from the distal end. This joint is also 

 furnished with three stout and moderately long terminal spines. Both 

 branches of the third and fourth pairs of feet are nearly equal and similar to 

 each other, except that the fourth is a little smaller (figs. 10, 11). Fifth pair 

 small, basal joint scarcely developed, produced exteriorly into an elongate 

 digitiform process, bearing a single apical seta, and furnished interiorly 

 with a very long and curved aculeate seta, the proximal part of which is 

 stout. The secondary branch (or joint) is foliaceous, spathulate in form, 

 the greatest breadth being rather less than half the length; the inner margin 

 nearly straight, bearing several minute teeth ; outer margin and end 

 sinuate and provided with a number of setae, the innermost being 

 nearly three times the length of the joint from which it springs (fig. 12). 

 The postero-lateral angles of the first abdominal segment are produced 

 into tooth-like processes. The postero-lateral angles of all the thoracic 

 and abdominal segments are acutely angular — the last abdominal segment 

 is very short — with the dorsal part of the posterior margin spiniferous, 

 the central spine being large and prominent, the others small. Caudal 

 stylets short ; the longest of the caudal setae are scarcely equal to twice 

 the length of the abdomen and caudal stylets combined. One ovisac. 



No males of this form have yet been observed in the Firth of Forth, 

 but females are frequent. 



This appears to be the form described in the monograph of the British 

 Copepoda as the ' male ' of Longipedia coronata. It also closely agrees 

 with the description and figures of Claus, both as regards its size and 

 structural details, with the exception of the arrangement of the spines on 

 the long joint of the inner branches of the second pair of swimming feet. 

 Claus's figure agrees with that of Giesbrecht in this respect. But the 

 form now described does not agree with that described by Giesbrecht in 

 size, in the form of the second and fifth pairs of thoracic feet, and in some 

 other important points. That described by Giesbrecht, on the other hand, 

 agrees perfectly with a form recently discovered by my son, Andrew Scott, 

 while examining some dredged material from the Firth of Forth, and 

 which is provisionally described as Longipedia coronata, var. minor. The 

 following is a description of this variety : — 



