66 BRITISH COPEPODA. 



1. DYSPONTIUS STEIATUS, Thorell. PI. XCII, figs. 1 13. 



Dyspontius striatus, Thorell. Om Krustaceer i Ascidier, p. 81 

 tab. xiv, fig. 22 (1859). 



Anterior antennae (fig. 2) 9 -jointed in the female 

 (10-jointed, Thorell), 11-jointed in the male (fig. 3) ; 

 the following formulae represent the relative lengths of 

 the antennal joints in the two sexes ; female : 



1, 2, 3. 4, 5, 6, 7, 8. 9; 

 5712 1| 2235 



male : 



1, 2, 3, 4. 5. 6. 7. 8, 9, 10, 11; 

 56111* 1142 3 1 



all the joints are sparingly setose on the outer margin, 

 the last bearing, in addition to several apical setae, a 

 long olfactory rod ; in the 'male the eighth joint has a 

 small blunt hook on the outer margin ; the last joint of 

 the female antenna is marked near the apex with' 

 several surface irregularities, which obscure its struc- 

 ture, but it appears to be undivided. Posterior 

 antennae (fig. 4) 3-jointed, the first joint bearing a 

 very minute, almost obsolete, secondary branch ; last 

 joint armed with three apical spines, that in the middle 

 long' and strong, the outer scarcely half as long, and 

 the innermost extremely small. Maxillae (fig. 5) com- 

 posed of two slender digits, one bearing two, the other 

 one long, apical seta ; mandibles and foot-jaws like 

 those of Artotrogus. The first three pairs of swimming- 

 feet have both branches 3-jointed, the marginal spines 



