426 MR. G. S. BRADY ON 



Diaptomus longicaudatus, Lubbock. 



(Not Monoculus finmarchicus, Gunner). 



Common in the open sea; and between tide marks perhaps 

 the most abundant of all British species. 



2. Temora velox, Lilljeborg. 



In autumn when the brackish pools of salt-marshes have 

 become thoroughly warmed by the sun, this species occurs in 

 such situations in immense profusion. I have only on one or 

 two occasions met with a stray specimen amongst the weeds on 

 the sea- shore. 



Genus ISIAS, Boeck. 



1. Isias clavipes, Boeck. 



Isias clavipes, Boeck, loc. cit., p. 18. 



Superior antennae twenty-five-jointed, about equal in length 

 to the cephalothorax, joints short and broad at the base, and 

 gradually increasing in length to the nineteenth, which is about 

 four times as long as broad ; first fifteen joints of the male 

 antennas bearing each a single club-shaped, ciliated, auditory 

 seta : hinge joint of the twenty-one-jointed right male antenna 

 situated between the eighteenth and nineteenth joints ; eigh- 

 teenth joint formed by the coalescence of the normal eighteenth 

 and nineteenth, nineteenth by the twentieth and twenty-first, 

 twentieth by the twenty -second, twenty - third, and twenty- 

 fourth. Mouth organs and swimming feet as in Centropages ty- 

 picus. Fifth pair of feet two-branched, in the female having the 

 inner branch of one joint with two terminal setae, the outer 

 branch of three broad laminar joints, the second of which is 

 produced on the inner margin into a broad spinous process : in 

 the male the feet are somewhat similar, but the central joint is 

 destitute of the spinous process, and the terminal joint of the 

 outer branch of one side is expanded into a very broad lamina, 

 which is terminated by a broad ciliated seta. Abdomen of the 

 female, four — of the male, five-jointed. Length, exclusive of tail 

 setae, -iVth of an inch. 



