435 



Rostral prominence comparatively small, deflexed. Genital segment in female im- 

 perfectly subdivided. Caudal rami comparatively short. Anterior antenna} more 

 slender than in Tachidius, and composed of a greater number of joints. Posterior 

 antennae with the proximal joint distinctly subdivided, outer ramus rather fully 

 developed. Oral parts somewhat resembling in structure those in the genus 







Tachidiella. Posterior maxillipeds, however, clearly distinguished by the presence 

 inside the basal joint of a complex masticatory lobe clothed with several denti- 

 culated spines. 1st pair of legs with both rami 3-articulate, the inner one the 

 longer and bent in the middle. Inner ramus of the 2 succeeding pairs of legs 

 biarticulate, the outer 2 joints being coalesced, that of 4th pair distinctly 3-arti- 

 culate. Last pair of legs comparatively small, distal joint well defined, inner 

 expansion of proximal joint scarcely at all produced. 



Remarks. This new genus ought evidently to be included in the family 

 Tachidiidce, as defined in the main part of this work, as it exhibits in its structural 

 details some affinity both to the genus Tachidiella and to Pseudotachidius, though 

 differing conspicuously from both of them in certain points. The structure of 

 the posterior maxillipeds in particular is very peculiar and unlike that found in 

 any other Harpacticoid known to me. Only a single species of this genus has 

 hitherto come under my notice. 



Tachidiopsis cyclopoides, G. 0. Sars, n. sp. 



(Suppl. PL 51). 



Specific Characters Female. Body moderately slender, with the 2 divisions 

 sharply marked off from each other, whereby it assumes a pronouncedly cyclopoid 

 appearance. Anterior division oblong oval in outline, with the cephalic segment 

 rather large and broadly rounded in front; rostral projection triangular, deflexed. 

 Epimeral plates of the 3 succeeding segments small and rounded off; 5th seg- 

 ment much narrower than the preceding one, from which it is separated by a con- 

 spicuous constriction. Urosome a little shorter than the anterior division and much 

 narrower, tapering somewhat distally, its segments clothed with small spikes ; genital 

 segment comparatively large and somewhat depressed in its anterior part, last 

 segment slightly shorter than the preceding one, and having the anal opercle 

 finely denticulated. Caudal rami about the length of the anal segment and of 

 uniform width throughout, each with a small bristle outside near the end, apical 

 seta? normally developed. Anterior antenna? almost attaining the length of the 

 cephalic segment and composed of 9 well-defined joints clothed with compara- 

 tively short and simple seta?, 1st joint the largest, the 3 succeeding joints of 



