298 DR THOMAS SCOTT ON THE 



rounded apex ; the outer margin of the second joint is neaidy parallel with the inner, 

 and near the extremity of the joint both margins converge to the angular apex ; four 

 setae spring from the lower end of the outer margin and apex of this joint, and one from 

 the lower end of the inner mai-gin ; all the setae are moderately slender. Caudal rami 

 very short. 



Habitat. — Obtained on floating seaweed collected in the North Atlantic on 29th June 

 1904, between Cape Verde Islands and the Azores, Station 537, 29° 54' N., 34° 10' W. 



Remarks. — The form described above has a close resemblance to Harpacticus gracilis, 

 Claus, and it may ultimately have to be ascribed to that species. Meanwhile, as no 

 male specimens have been observed, and as there are one or two slight difierences 

 between the two forms, as, for example, in the structure of tlie antennules and of the 

 fifth pair of thoracic legs, it is perhaps better that the specimens from the Scotia's 

 collections should be recorded under a distinct name. 



Harpacticus piriei, new species. (PI. V. fig. 15 ; PI. XI. figs. 18-25.) 



Female. — Body moderately stout, somewhat resembling Harpacticus clielifer, 

 0. F. Mliller, in its general form. Length about 8 5 mm. 



Antennules composed of nine joints ; the first four tolerably stout and elongated, 

 the others small, so that, together, they are scarcely equal to a fourth of the eiitire 

 length of the antennule (fig. 18, PI. XI.). Antennae and mouth appendages nearly as 

 in Harpyacticus chelifer. 



The first pair of thoracic legs are tolerably slender, and somewhat similar to the 

 species mentioned ; the other three pairs are also somewhat similar to those in the 

 same species, except that in the second pair the inner ramus is nearly as long as the 

 outer one. 



The fifth pair has the basal joint broad and its inner portion only slightly produced, 

 and provided with four setae of unequal lengths on its distal margin, the second seta 

 from the outside being much longer than the others. The second joint is subtriangular 

 in outline, the greatest width, which is near the proximal end, being about equal to 

 half the length ; the inner margin is nearly straight, but the outer is rounded and 

 curves obliquely to the distal extremity : this joint is provided with six setae of un- 

 equal lengths — two, having a considerable space between them, on the lower half of 

 the outer margin, two close together at the apex, and two at the distal end of inner 

 margin — the second seta from the inside being very small (fig. 15, PL V.). 



The caudal rami in this species are very short. 



Habitat. — Scotia Bay, South Orkneys, in siftings from some dredged material 

 collected in 9 to 10 fathoms, in April 1903, Station 325, 60° 43' 42" S., 44° 38' 33" W. 



Remarks. — This species, though it resembles Harpacticus chelifer in some resj^ects, 

 differs distinctly in the form and armature of the fifth pair of thoracic legs, and also 

 in the structure of the antennules. Named in compliment to Dr J. H. Harvey Pirie, 

 one of the Scotia naturalists. 



(ROY. SOC. EDIN. TRANS., VOL. XLVIII., 544.) 



