lateral margins of the last metasomal segment 

 and the presence of 2 external spines on the 

 terminal exopodal segment of the first leg (fig. 

 2). By the setation of the mandibular palp, the 

 specimens of the present collections can be di- 

 vided into two forms that Johnson (1938) de- 

 scribed as subspecies — E. bungii bungii, which 

 has 3 setae on the basis of the palp (fig. 1), 

 and E. bungii californicus, which has a single 

 seta on this structure (fig. 3). Since these two 

 forms are distingiii-shable from each other only 

 on the basis of this apparently insignificant 

 character, however, it seems better to recognize 

 them as ecophenotypic variants than as 

 subspecies. 



Finding all possible transitions between Gies- 

 brecht's (1892) varieties hyalinus and bungii 

 in the SneUius plankton samples, Vervoort 

 (1946) disagreed with Johnson's (1938) idea 

 of elevating these varieties to specific level. The 

 present materials, however, are in favor of 

 Johnson's (1938) treatment in the absence of 

 any intermediate forms. 



Mecynocera clausii Thompson, 1888 

 Occurrence 



Sta. 5. 4 adult females, 1.05 to 1.08 mm. ; 



1 fifth copepodid male, 0.99 mm. 

 Sta. 7. 5 adult females, 1.05 to 1.15 mm. ; 



2 fifth copepodid males, 0.99 mm. 

 Sta. 9. 1 adult female. 1.08 mm. 



Remarks 



This species can be recognized by the excep- 

 tionally long antennule, which is about twice 

 as long as the body, and the comparatively 

 small size of the copepod itself. According to 

 T. Scott (1894), the fifth leg in both sexes of 

 this species is 5-segmented. The three males 

 in the present collections have 4-segmented 

 fifth legs and 4-segmented urosomes, indicating 

 that they are immature. 



FAMILY PARACALANIDAE 



Paracalanus parvus (Glaus, 1863) 

 Occurrence 



Sta. 13. 1 adult female, 1.00 mm. 

 Remarks 



I find it curious that we took only one speci- 

 men of this reportedly cosmopolitan species. 



Calocalanus pavo (Dana, 1849) 



Occurrence 



Sta. 5. 2 adult females, 1.08 to 1.12 mm. 

 Sta. 7. 10 adult females, 1.05 to 1.18 mm. 



Remarks 



Although widely distributed in the tropical 

 and subtropical regions of all three great 

 oceans, this species was found at only two of 

 the stations. 



Calocalanus tenuis Farran, 1926 

 (Plate 4, figs. 4-9) 



Occurrence 



Sta. 13. 4 adult females, 1.15 to 1.24 mm. 



Description of Female 



The body (figs. 4 and 5) is slender and fusi- 

 form; the anterior end of the cephalosome is 

 vaulted. The cephalosome and the first meta- 

 somal as well as the fourth and fifth metasomal 

 segments are completely fused. The urosome 

 consists of 3 free segments and the caudal 

 rami. The segments and caudal rami have the 

 following proportional lengths, from anterior 

 to posterior: 38:15:32:15. The genital segment 

 is slightly broader than long in the proportions 

 of 56:44. The caudal ramus is about as broad 

 as it is long. 



The first leg (fig. 6) has a 3-segmented exo- 

 pod and a 2-segmented endopod. The coxa has 

 a seta on the internal margin. The exopod has 



0, 0, 2 external spines, 1, 1, 4 internal setae, 

 and a terminal seta. The endopod has 1, 2 in- 

 ternal setae and 2 terminal setae. 



The .second leg (fig. 7) carries a plumose seta 

 on the internal margin of the coxa. The 3-seg- 

 mented endopod has 1, 2, and 7 setae, respec- 

 tively. There are 4 spines, in a transverse row, 

 on the posterior surface and 4 spines on the ex- 

 ternal margin of the second endopodal seg- 

 ment. The exopod is also 3-segmented, with 1, 



1, 2 external spines and 1, 1, 5 internal setae 

 in addition to a terminal .seta. The posterior 

 surfaces of the first and second exopodal .seg- 

 ments carry 3 and 6 spines, respectively. 



The endopod of the third leg (fig. 8) is 3- 

 segmented. The segments have 1, 2, 7 setae, as 

 does the endopod of the second leg. In addition, 

 the second segment has 6 spines on the poste- 

 rior surface and 4 spines on the external 



540 



U.S. FISH AND WILDLIFE SERVICE 



