120 BRITISH COPEPODA. 



inner branch ciliated on the upper half of the inner 

 margin, but destitute of long setse ; terminal claws two, 

 long, slender, and only slightly curved. " On the 

 lower borders of the four last body segments, and, in 

 the female, also on the line between the first and 

 second abdominal segments, a row of minute teeth. 

 The last abdominal segment shorter than the preced- 

 ing ; the caudal segments very short and broad ; the 

 inner tail seta longer than the abdomen, the outer 

 scarcely half as long. Two ovisacs." Glaus. 



My observations of this species have not been so 

 full as might be wished, owing to a scanty supply of 

 specimens. Possibly it ought to come under Boeck's 

 genus Diosaccus ; but I have no doubt whatever of the 

 identity of my specimens with D. minutus, Glaus. They 

 occurred very sparingly in a tow-net gathering, taken 

 at dusk, in Westport Bay, Ireland. 



Genus 25. THALESTRIS, Glaus (1863). 



Body slender and elongated, or broad and depressed. 

 Anterior antennae 9-jointed (sometimes 8- or 6-jointed, 

 Boeck). Inner branch of posterior antennae 2- or 3- 

 jointed. Mandible-palp large, 2-branched, the inner 

 branch usually the largest. Masticatory portion of 

 the maxilla provided with numerous strong teeth ; palp 

 large, its terminal segment usually armed with a large 

 claw; lateral segments sometimes reduced to a few 

 bristles. First pair of foot- jaws ending in a strong 



