COLLECTED BY CAPTAIN TOYNBEE. 177 
distinctly six-jointed, — the anterior portion, including the base of the maxillipeds, being 
separate from the five segments bearing the natatory feet. In some specimens, uhich in 
other respects were like the remainder, the antennae were rather shorter than usual. It 
would be very desirable to ascertain, by the examination of a number of specimens, how 
much variation exists in this character. Prof. Dana describes the two posterior subapical 
setae of the anterior antennae as " subequal ;" in all my specimens the antepenultimate 
seta was distinctly the larger of the two. 
According to Mr. Toynbee's notes, his specimens had red antennae and feet ; while Prof. 
Dana's were of a faint purplish-blue colour. 
Of two specimens which were captured on the 15th of December 1858, each had two 
spermatic tubes attached to the posterior part of the cephalothorax. The specimens in 
question had the segments of the abdomen gradually decreasing in length, the basal being 
at least half as long again as the second segment. 
This species was met with on several occasions. 
Collected October 25. S. lat. 13° 43' : W. loner. 33° 55'. 
s> 
)> 
» 
November 4. S. lat. 33° 27' ; W. long. 30° 28', 
November 22. S. lat. 40° 53'; E. long. 45° 22'. 
December 14. S. lat. 5° 49'; E. long. 83° 17'. 
** Cephalothorax siiperne visits postice acutus, angulis p ostitis non appressis. 
C ALAN US BREVICOKNIS, Lbk. 
This species may at once be distinguished from Calanus setuligerus, which it otherwise 
much resembles, by the shortness of the antennae, and by the front being produced in 
front of the stylets and of the base of the antennae. The cephalothorax was five-jointed 
in my previous specimens ; in the present individuals it had six segments — an important 
variation, which appears also to occur in C. setuligerus. 
Collected November 22, 1858. S. lat. 40° 53'; E. long. 45° 22'. 
» 33 
S. lat. 0° 30' ; W. long. 0° SO 7 . 
Calanus communis, Dana. 
Collected October 7th. N. lat. 7° 15'; W. long. 2j° 2'. 
„ June 22nd. S. lat. 0° 40' ; W. long. 0° 20'. 
Cala 
Prons rotundatus. Cephalothorax 5-articulatus, superne 
angulis posticis acutis, non appressis ; latere visus rotundatus, inermis. Antennae 
anticaa corpore paulo breviores, setis apicalibus brevibus, antica penultima elongata, 
postica penultima antepenultimaque longioribus subaequis. Abdomen 4-articulatum, 
stylis caudalibus brevibus, setis mediocribus, secundis longioribus. 
In general outline, in the proportion of the cephalothoracic and abdominal segments, 
and in the setae of the anterior antenna?, this species very closely resembles C. communis, 
from which, however, it differs in the relative shortness of the antenna?, and in having the 
cephalothorax unarmed behind. It is true that Dana makes no mention of the lateral 
cephalothoracic hook ; but it was present in all the specimens examined by me which 
possessed the other characters of the species. 
