120 BRITISH COPEPODA. 



backwards. Anterior antennae much shorter than 

 first segment of cephalothorax, 6-jointed, stout at the 

 base, and only slightly tapering towards the apex ; 

 fourth and sixth joints much the longest, third and 

 fifth very short. Mandibles dilated at the apex and 

 divided into several slender, sharp teeth. Upper 

 foot-jaws very slender. Maxillse (PI. XIX, fig. 10) 

 strongly toothed, divisions of the palp short but 

 strongly setose. Fifth feet composed of a small basal 

 joint and a triangular lamina, dilated towards the 

 extremity, and bearing on the distal margin three 

 spines and one seta of moderate length ; outer and 

 inner margins finely ciliated. Abdomen slender, the 

 first joint about equal in length to the following two ; 

 last segment very short, and scarcely equal in length 

 to the caudal segments, which are scarcely twice as 

 long as broad. Outer and inner tail setae very 

 short ; innermost of the two intermediate setae the 

 longest ; about equal in length to the abdomen ; both 

 are fringed with fine short cilia. Ovisacs large 

 and almost adpressed. Length -^jth of an inch 

 ('85 mm.). 



Cyclops cequoreus is probably a pretty common 

 inhabitant of the brackish pools of salt marshes. In 

 such situations I have found it at Seaton Sluice 

 (Northumberland), Manningtree (Suffolk), Pwllheli 

 (North Wales), Clifden (Ireland), and at St. Mary's 

 (Scilly). I have also specimens taken by Mr. Robertson 

 near Belfast, and by the Rev. A. M. Norman in the 

 West of Scotland. Fischer's specimens were taken in 

 pools near the sea at Madeira, but the species does not 



