254 Part III. — Thirteenth Annual Report 



Ophioeamptus brevipes (G. 0. Sars), (PI. X. figs. 1-9). 



1862. Canthocamptus brevipes, G. 0. Sars, ' Oversigt. af de ind. 

 Ferskvaudscopepoder ' : Forhandl. Vedensk. Selsk. Christiania 

 (1862). 



1893. Ophioeamptus brevipes, Al. Mrazek, ' Beitrag zur Kenntniss 

 der Harpacticiden fauna des Siisswassers ' : Zoologischen 

 Jahrbuchern ; Siebenter Band, p. 116, Taf. 5, fig. 66; Taf. 

 6, figs. 67-70. 



Description of the species. — Female, length *72 mm. (about ^g- of an 

 inch). Body slender, in general appearance somewhat like Ophioeamptus 

 sarsii, Mrazek ; antennules seven-jointed, the end joint is rather longer 

 than any of the others, as shown by the formula — 



Proportional lengths of tbe joints, 9 • 9 • 8 • 7 ' 8 ' 8 • 1 2 

 Number of the joints, 1 '2'3'4'5'6' 7 



Antennae and mouth organs somewhat similar to those of Ophiocamp 

 tus sarsii. The first pair of swimming feet also resemble those of that 

 species, but the inner branch is proportionally longer, being about equal 

 in length to the outer branch ; the end joint of the inner branch is pro- 

 portionally rather longer and narrower in relation to the first joint than 

 the end joint of the inner branch of the first pair in Ophioeamptus sarsii ; 

 the armature of the first pair also differs in the two species, — in Ophio- 

 eamptus brevipes the marginal spines are of greater length, and the apical 

 setae also more elongate (fig. 6). 



The second, third, and fourth pairs are all very much alike; in the 

 fourth pair, the end joint of the outer branches bears exteriorly two stout 

 subterminal hairs of unequal length, — the inner being nearly twice the 

 length of the outer ; the apical seta is long and spiniform, it is fully one 

 and a half times the entire length of the outer branch ; on the interior 

 side of the apical seta are two subterminal setse, of nearly equal length 

 and more slender than the others, they are each fully half the length of 

 the apical seta; the first joint of the very short two-jointed inner branch 

 bears a slender spine on the distal half of the inner margin, and four 

 small setae round the end of the last joint (fig. 7). In the fifth pair, the 

 produced inner part of the basal joint is narrow, cone-shaped — the length 

 being about one and a half times the breadth at the base ; the secondary 

 joint is narrow, subcylindrical, and reaches to the apex of the basal joint ; 

 both joints are furnished with setae of considerable length, some of which 

 are plain, they are arranged as shown on the drawing (fig. 8). Caudal 

 stylets somewhat similar to those of Ophioeamptus sarsii (fig. 9). 



Habitat. — Loch Lubnaig, Perthshire, altitude 405 feet above sea-level. 

 Apparently rare. 



Remarks. — This species, which somewhat resembles Ophioeamptus 

 sarsii in general appearance, is at once distinguished from it by the form 

 and armature of the fifth pair of thoracic feet, and, as a matter of fact, 

 this forms its most marked characteristic. In most of the other characters 

 it approaches very near to Ophioeamptus sarsii. 



The species was described by G. O. Sars in 1862 as Canthocamptus 

 brevipes. In 1893 it was re-described by Al. Mrazek under the new 

 genus Ophioeamptus that he had instituted for the reception of this and 

 one or two other aberrant forms of Canthocamptus. One of these others 

 was Canthocamptus gracilis, Poppe (not the Canthocamptus gracilis, G. O. 

 Sars), the name of which he changed to Ophioeamptus sarsii. 



About the same time, the genus Ophioeamptus was instituted by 

 Mrazek, a description of the genus Moraria, T. and A. Scott, was 

 published in the Annals and Magazine of Natural History. It turned 

 out afterwards th;it the characters of these two genera were found to be 



