16 Mr. Lubbock 



pendage is formed as usual, but is about six times as long as the 

 two apical segments of tlie organ itself. Length "OSS. 



Length of the second pair of maxillae . . '02 

 ,, maxillipeds 'Oi5 



There is nothing peculiar in the forms of these two pairs of ap- 

 pendages, which resemble those of other Ccdani. 



Ihe first pair of natatory feet is "025 in length, and very closely 

 resembles that of Und'inn pulchra. (PI. IV. fig. 6.) 



Tlie fourth pair is •04< in length, and appears to me to be exactly 

 similar to that of Und'ina pulchra. (PI IV. fig. 7.) 



The exact similarity of the natatory legs in these two species, 

 coupled with the fact that I only know the male of the one and 

 the female of the other, force on us the consideration whether they 

 are not the different sexes of the same species. It may be so cer- 

 tainly, but the difterence in both pairs of antennae and in the max- 

 illipeds have induced me to describe them as separate. 



Length of cephalothorax, '110; of abdomen, '05. 



Collected in N. L. 31° 50' ; W. L. 18° 30'. 



Most of the specimens had spermatic tubes attached to the ab- 

 domen. PI. II. fig. 12 and PI. XI. figs. 8, 11. 



II. Setae antennarum anticarum apicales subapicalibus non 

 longiores. 



Calanus communis, Da. 



There are a number of specimens which agree in most points 

 with Dana's description of this species. The apical segment of 

 the anterior antenna in my specimens was, however, rather shorter 

 than the preceding, and the second of the abdominal setae is quite 

 twice as long as the others. 



Professor Dana gives no side view; PI. X. figs. 9, 10, represents 

 the outline of the posterior segment of the cephalothorax ; the 

 hooked spine exists in every position between the two in which I 

 have figured it. 



Collected in the Atlantic by Dr. Sutherland, from 12° 30' N. to 

 32° 50' S. L., and from 19° to 26° W. L. ; by Dana from 8° N. to 

 5° S. L., and from 15° to 30° W. L. PI. X. figs. 9, 10. 



Calanus 7/iirabilis. 



Frons subacuta, lateribus inflata. Cephalothorax 5-articulatus, 

 gracilis, postice obtusus. Antennae anticae corpore longiores, 

 setis brevibus apicalibus tamen, et setd anticaarticuli ab apice 

 quarti, longis, et postica penultima praelongd. Antennarum 



