209 



pair of legs with the inner expansion of proximal joint extending scarcely beyond 

 the distal joint and provided with 3 comparatively short setse. 



Colour whitish, with a more or less distinct yellowish green tinge. 



Length of adult female 0.67 mm. 



Remarks. This form was first described by Prof. Lilljeborg, but errone- 

 ously identified by him with Canthocamptus Stromi of Baird, for which reason 

 Boeck proposed for it the above specific name, regarding it moreover as the type 

 of his new genus Mesochra. The form subsequently recorded by Mrss. Brady and 

 Kobertson under the name of Paratachidius gracilis is the same species. 



Occurrence. This is a strictly littoral form, occurring rather plentifully 

 in many places both of the south and west coasts of Norway, at least up to the 

 Trondhjem Fjord. It is generally found close to the beach in shallow bays, 

 where the water is more or less brackish. Like other littoral species, it is not 

 seldom left in tidal pools, but is scarcely ever found in purely fresh water. 



Distribution. Coast of Sweden (Lilljeborg), British Isles (Brady), bay of 

 Keel (Giesbrecht), coast of France (Canu), Novaja Zemlia (Scott). 



132. Mesochra pygmaea (Glaus). 



(PI. CXXXVI). 

 Dactylopus pygmceus, Claus, Die fi-eilebenden Copepoden, p. 127, P). XVII, fig. 3. 



Syn: Canthocamptus parvus, Scott. 



Specific Characters. Female. Body comparatively short and stout, attenu- 

 ated behind. Cephalic segment rather large, exceeding somewhat in length the 3 

 succeeding segments combined, rostral projection less prominent than in the pre- 

 ceding species. Last segment of urosome shorter than the preceding one. Caudal 

 rami very short, being scarcely as long as they are broad, and transversely trun- 

 cated at the tip, apical setse rather elongated and somewhat thickened at the 

 base. Anterior antennae rather small and only composed of 6 joints, the 3rd and 

 4th being coalescent, terminal part nearly as long as the proximal one. 1st pair 

 of legs with the outer ramus scarcely more than half as long as the inner and 

 somewhat curved at the base, middle joint without any seta inside; inner ramus 

 distinctly 3-articulate, with the 1st joint somewhat dilated at the base and having 

 the seta of the inner edge attached in front of the middle, last joint a little 

 longer than 2nd, and both together not attaining half the length of the 1st. 

 Natatory legs of a very similar structure to those in the type species. Last pair 

 of legs likewise rather similar, though having the distal joint somewhat larger 



