Gatty Marine Laboratory, St. Andrews. 83 



In his original description Malmgren describes the branchiae 

 as four pairs, the basal reo^ion of the long taj^ering forms as 

 pinnate, the distal as filiform (referiing to the elongate 

 pinnate organs of the front and rear of the anterior region). 

 He, however, observes that these are longer than the branchias 

 of his second and thii'd segments (for he apparently over- 

 looked the minute anterior feet), yet he does not differentiate 

 these from the dorsal lamellae of the feet, which are truly 

 lanceolate, whilst the true branchiae, which he appai'cntly 

 represents in his fig. 55 A, Taf. x-, are broadly strap-shaped, 

 only a little tapered at the tip, which ends in a conical 

 process or mucro. Moreover, they are closely striated trans- 

 versely and richly ciliated, whereas the pinnate processes and 

 the lamellae of the feet are not. Claparede, again, expressed 

 doubt as to the actual nundDer of brancliiae, from the facility 

 with wdiicli these delicate organs break off. He, however, 

 considered the pinnate cirri as branchiae, though he found no 

 cilia on them. lu his figure (pi, xxii. fig. 3) none of the 

 ligulate (true) branchiae are shown, and the position of the 

 posterior pair of the pinuate cirri is faulty. 



In the first foot the dorsal and ventral lamellas are rounded 

 and rudimentary, and the tufts of bristles small ; moreover, 

 the granular condition of the axis of the bristle was not made 

 out. The second foot has the dorsal lamella of a lanceolate 

 outline, whilst the ventral is rounded. Both dorsal and 

 ventral bristles showed a granular condition of the axis, so 

 that it (axis) appeared to have minute transverse bars in the 

 centre (PI. Yl. fig. 6). 



In the third, fourth, and fifth feet the dorsal lamella, 

 largely increases in size as a broadly lanceolate process, but 

 in the third and fourth it is considerably less than the 

 elongate branchia which forms a conspicuous process on the 

 inner side of each, and readily distinguished by tlie trans- 

 verse lines. These branchiae are much longer than those in 

 the Canadian form, and the tip differs in its tapered con- 

 dition. They are also proportionally larger and longer than 

 in the P.plumosa of Sars. The first ten segments are con^ 

 spicuously bristled, the strongly curved dorsal and ventral 

 bristles projecting laterally in front of the lamellae. The 

 eleventh has more slender capillary bristles, Claparede 

 stated that the hooks commenced on the filteenth segment, 

 but Mr. Southern described them on the twelfth bristled 

 segment. When this feature was examined the specimens 

 were much injured, so that exactitude was not possible. 

 They seemed to begin about the fourteenth or fifteenth. 



The three forms mentioned above, viz., Malmgjen's, Sars's^ 



6* 



