334 



Gen. 77. Robertsonia, i;ia<i\. LSSO. 



Generic I'l/m-urf, is. -Body not depressed. almost cylindric in form, though 



tapering behind. with no very sharp demarcation of the '2 divisions. Rostrum 

 prominent, well defined behind. (-ienital segment imperfectly subdivided in female. 

 ( 'audal rami short. Anterior antenna' coinparatively short and stout, with the 

 number of joints somewhat reduced: those in male distinctly hinged. Posterior 

 antenna- with the proximal joint not subdivided, outer minus well developed. 

 though composed of only '2 joints. Oral parts normal. 1st pair of legs only 

 slightly differing in structure from the 3 succeeding ones, inner ramus 3-articulate 

 and about the length of the outer: inner ramus of *2\\(\ pair of legs in male 

 conspicuously transformed. Last pair of legs of normal appearance, with both 

 joints \\ell defined. 



Remarks. -This genus was established in the year 1880 by Prof. Brad\, 

 and was referred by that author to his sub-family Tticltidiht"-. I am also of 

 "pinion, that this genus is more properly referable to the present family, although 

 the general form of the body is rather unlike that in the typical genus T<ichniu<*, 

 Only one species has as yet been observed. 



214. Robertsonia tenuis, Brady. 



(PI. <'< XXII). 



/r/M'/'.s, Ili'inly. .M . nn ILT. . !' lint. Cnpepoda, \'<>l. II, p. 2">, 1M. XLI. li--. 1 14. 



/ic ( 'liiii-ni-li'f.s. l-'niiuli'. Body moderately robust, somewhat dilated 

 in front, and rapidly tapering behind. Cephalic segment large and deep, fully 

 equalling in length the 4 succeeding segments combined ; rostrum rather prominent 

 and narrou triangular in form, tip obtusely acuminate. Epimeral j)lates of the 

 :; siici ceding [segments well developed and acutely produced at the posterior 

 corner. Last pedigerous segment almost as broad as the preceding segment. 

 Urosome somewhat exceeding half the length of the anterior division, and gradually 

 taperin- distally. posterior edge of the segments coarsely spinulose. genital segment. 

 fully as long, as the remaining segments* combined. Caudal rami broader than 

 they are long and obtusely truncated at the end. edges partly spinulose. apical 

 seta' of moderate length and normal st met lire. Kye distinct though rather small. 

 Anterior antenna' much less than half the length of the cephalic segment. 

 and rather densely clothed \\ith comparatively short, partly ciliated seta 1 , being 

 compo-ed of ."i joints onl\. .'! of them belonging to the proximal part, terminal 

 part about hall' the length of the latter, with the 1st joint \<T\ small. Posterior 



