254 



Part III. — Seventeenth Annual Report 



Rohertsonia tenuis (G. S. Brady and Robertson). 



1875. Edinosoma tenue, B. and R., " Proceed, of the Brit. Ass.," 

 p. 196. 



A few specimens of this well-marked species occurred in a small 

 gathering of Microcrustacea from Station XVI. (Moray Firth), depth 30 

 to 40 fathoms, collected on 10th June 1 898. The gathering consisted of 

 the washings of some dredged material. 



Delavalia mimica, T. Scott. 



1897. Delavalia mimica, T. S., Fifteenth Ann. Rep. Fish. Board 

 Scot., Pt. III., p. 150, PI. I., figs. 1-9. 



This species was obtained in a gathering from Station XVI. (Moray 

 Firth), collected on 10 th June 1898, but was somewhat rare. 



Delavalia cemula, T. Scott. 



1893. Delavalia cemula, T. S., Eleventh Ann. Rep. Fish. Board 

 Scot., Pt. III., p. 204, PI. IV., figs. 36-47. 



This species was obtained in some dredged material collected a little to 

 the west of Invergordon, and was also somewhat rare. 



Delavalia giesbrechti, T. and A. Scott, var. (PI. XIII. , figs. 20-22), 



1890. Delavalia giesbrechti, T. and A. S., Ann. Scot. Nat. Hist., 

 p. 225, PI. IV., figs. 1-10. 



A form of Delavalia has been obtained at Hunterston, Firth of Clyde, 

 which resembles Delavalia giesbrechti very closely, but it wants the 

 peculiar broad tail setae that constitute such a marked feature in that 

 species (fig. 22) ; there is also a slight difference in the arrangement of the 

 four marginal setae on the inner portion of the basal joints of the fifth 

 thoracic feet (fig. 21). In other respects the two forms appear to be 

 similar. Fig. 20, which represents the first pair of swimming feet, shows 

 the second joint of the inner branches to be rather more slender than 

 the same joint in typical D. giesbrechti. 



Psyllocamptus, gen. nov. 



Similar to Canthocamptus, but the inner branches of the first pair of 

 swimming feet, which are about equal in length to the outer branches, 

 are two-jointed, while the inner branches of the next three pairs are all 

 three- jointed. Moreover, the antennules in spirit specimens are distinctly 

 bent at the second joint as in Nitochra. 



Psyllocamptus fairliensis, sp. n. (PI. XIII., figs. 12-19). 



Description of the Female. — Length about '6 mm. (^L of an inch). 

 Body slender and elongate, and resembling Canthocamptus in general 

 appearance (fig. 12). Antennules moderately short and setiferous, eight- 

 jointed ; the first two robust, the penultimate joint smaller than the 

 others (fig. 13) ; the formula shows approximately the proportional 

 lengths of all the joints — 



Number of the joints, 1 -2 •3 , 4'5-6'7 , 8 



Proportional lengths of the joints, 24 • 24 • 7 " 9 ■ 6 • 7 ' 4 ■ 6 



Antennce short, three-jointed ; secondary branch small, one-jointed, 

 and furnished with three setaa (fig. 14). 



