114 Transactions. — Zoology. 



apex. First and second pairs of foot-jaws simple, bearing a strong apical 

 claw, first of two, second of four joints. First four pairs of foot having 

 both branches 3-jointed : fifth pair 2-jointed. 



1. Acontiophorus scutatus, Brady and Eobertson. (Monogr. of Brit. 

 Copepoda, vol. hi., p. 69). PL VIIL, figs 9-14. 



The following description is taken from Brady's Monograph, and agrees 

 exactly with our form : — 



" Body sub-pyriforrn ; cephalothorax broadly ovate ; head united with 

 the first thoracic somite, the segment thus formed being very large and 

 equal to nearly half the entire length of the body; abdomen of the female 

 3-jointed (of the male 4-jointed), the first segment large, and composed of 

 two coalesoent somites. Posterior angles of all the body-segments rounded 

 off, or only very slightly produced. Anterior antennae very short, scarcely 

 one-third as long as the first segment of the body, stout at the base, and 

 gradually tapering to the apex, densely clothed on the outer margin and 

 apex with long fine hairs, some of which are plumose; to the seventh joint 

 is attached a long curved olfactory appendage. The relative lengths of the 

 various joints is represented by the following formula : — 



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

 9. 7. 2. 1. 2. 5. 2£. 2J. 3. 3. 4. 



" Posterior antennae 4-jointed, with two strong lancet-shaped spines at 

 the apex of the last joint, together with one long and four or five very short 

 setae ; at the base of the external margin are also a few small setae ; the 

 second joint gives origin to a 1-jointed secondary branch, which terminates 

 in a long plumose seta. Mandible simple, consisting of a short stout ped- 

 uncle bearing a very long plumose seta." (Mr. Brady adds, " Probably also 

 a filiform palp, though I have not seen this." I have not been able to detect 

 any trace of a palp either, but have not had a sufficient number of speci- 

 mens to examine.) •" Maxilla? composed of two stout digits (or digit-formed 

 processes), one of which bears three, the other four stout, curved, and 

 densely plumose setae." Basal joints of both pairs of foot-jaws stout, ter- 

 minal claws elongated, curved — "Outer and inner branches of the swim- 

 ming-feet nearly equal in length, 3-jointed, all the joints much constricted 

 at the base, first and second joints dilated at the apex, third elongated and 

 narrow ; the distal margins of the first and second joints are strongly 

 dentated, and in the inner branch are, at the outer angles, produced down- 

 wards into sharp spines ; the marginal spines of the outer branch are long 

 and dagger-shaped, the last joint of both branches bearing a long subulate 

 and much attenuated apical spine. Fifth pair of feet stout, 2-jointed, first 

 joint shorter than broad, and bearing one long seta, second longer than broad, 

 and furnished with five long, subequal, terminal setae. Caudal segments 



