116 NOTES ON THE COPKPODA OF THE 



The endopodite of the posterior foot-jaw is only one-tliird as long 

 as the second basal, which again is very much longer than the first 

 basal (proportions 11 : 19:6). The anterior anienn;e are a little longer 

 than the thorax, with the twenty-fifth joint partially divided from the 

 twenty-fourth (eighth coalesced with ninth), and the head is separated 

 by a dorsal line from the first thoracic segment. This Copepod is 

 entirely different from E. pidclira, galatea, or cnrticauda, especially in 

 the proportions and number of bristles of the posterior antennae, and 

 the absence of any spines on the first basal of the fourth feet. It 

 occurred at a depth of 400 fathoms, lat. 5.5° 47' N., and also in tlie 

 Faroe Channel. 



la. Eiickinila curticauda, var. Atlantica. Head with strong crest 

 and lielmet, but no rostrum ; genital segment very protuberant, and 

 abdomen very short (about one-sixth the length of the cephalothorax) ; 

 endopodite of posterior foot-jaw only one-half the length of the second 

 basal, the three joints proportionate respectively 10:13:6; posterior 

 antennas with very slender endopodite, only one-quarter the length of 

 the exopodite, and end joint of the former with only 3 4- 2 bristles ; 

 head separate from the first thoracic segment ; maxilla with bristles of 

 second basal and endopodite much reduced ( = 6). The basals of the 

 fourth feet have only six rather broad-based and long spines, instead of 

 twelve to thirteen, as in E. curticauda (Gbt.), and also they differ in 

 some minor particulars. The latter is also a Pacific Ocean species, 

 the Atlantic variety being a little larger (3"80 mm.) than the Pacific. 

 The Atlantic form is a distinct variety if not a true species, and 

 the widely different habitats suggest specific differences. In the warm 

 area of the Atlantic, lat, 54° 30' N., it occurred at 300 fathoms. 

 Probably the E. curticauda of the " Oceana " collections (nine stations 

 from 809-1,710 fathoms) is this, or the previous species. 



8, ^tideus tenuirostris {nov. sp.). It is certain that the yEtidcus 

 arrnatus of the Faroe Channel and North Atlantic is not identical 

 with that described by Giesbrecht from the Mediterranean, with which 

 I have compared it at Naples. The former has a much less pronounced 

 dorsal cephalic curve ; the rostrum is not nearly so strong or so greatly 

 produced, nor does it possess (as Sars has pointed out already) any 

 secondary knobs of chitin at the base of the rostral processes as in the 

 Mediterranean species. In addition the spines of the last thoracic 

 segment are not so long or strong, and the endopodite of the second 

 pair of feet is biarticulate. It therefore seems desirable to distinguish 

 it as a distinct species. Brady's Indian Ocean species {Chcdl. Report) 

 has not again been met with. I do not find any /Etideus in Mr. 



