CERATIUM SPECIES OF CARNEGIE COLLECTION 



41 



trichoceros occiirred at eighty-six stations- -fourteen in 

 the Atlantic and seventy-two in the Pacific. The total 

 number of sample records for the species was only 181, 

 of which 89 were rare, 67 occasional, 24 common, and 1 

 abundant. The net records numbered 118; the pump rec- 

 ords, 63. Peters (1934) found it widespread in the warm 

 South Atlantic but principally In his region I and along 

 the west coast of Africa. Nielsen (1934) found it through- 

 out the region from Panama to Australia. 



According to the Carnegie distribution this is a 

 rather strictly tropical species. In the Atlantic it was 

 confined to the warm Atlantic region, with surface tem- 

 peratures from 21.°2to 28.°5 C. In the Pacific it was con- 

 fined to the warm Pacific region and the southeast Pa- 

 cific region. The total range of surface temperatures in 

 the Pacific was from 19.°0 to 29.°5 C. The total ranges 

 of environmental conditions in situ were: temperature, 

 14.°0 to 29.''4 C; salinity, 31.7 to 37.1 per mille; pH, 7.82 

 to 8.47; phosphate, 2 to 159 mg P04/m3. 



The Carnegie data do not show any preference on 

 the part of this species for any particular type of water 

 within the warm-water regions. It does not shun oligo- 

 trophlc water. Of the 181 records of occurrence, 63 

 were from water containing less than 10 mg P04/m3. 



It is uncertain at what depth this species normally 

 lives most abundantly. Nielsen (1934) stated that it was 

 always more abundant in his 50- to 0-meter samples. In 

 the Carnegie collection, however, there were more rec- 

 ords for 100 meters than for the upper levels, with the 

 fewest records for the svtrface (see table 44). 



Table 44. 



Records of occurrence of C. trichoceros 

 at three levels 



A=Number of records. B=Per cent of total nimiber of 

 samples collected at that depth. 



52. Ceratium vultur Cleve 

 Figures 23A-H, chart 43, appendix table 48 



The species as here considered Includes C. simiatra- 

 num (Karsten) Jorgensen and C. pavlllardii Jorgensen. 

 Ceratium vultur is a variable species with many variable 

 characters giving rise to what seem, at times, separate 

 species. The study of the extensive material of the Car- 

 negie collections, however, convinced the authors that 

 these are variants of a single large species. The inter- 

 grades between them are numerous. Peters (1934) and 

 Nielsen (1934) have already considered C. vultur and C, 

 sumatranum as a single species, with sumatranum a va- 

 riety of the former. In our material it was possible to 

 distinguish seven different varieties as follows. 



Variety vultur (Cleve) is stout and long-horned (fig. 

 23H). The right antapical ascends moderately; the left 

 antapical extends posteriorly less than 0.5 girdle width 

 before turning anteriorly. 



Variety iaponicum (Schroder) is as above, except that 



the left antapical extends posteriorly more than 0.5 girdle 

 width before turning anteriorly (figs. 23E-F). 



Variety sumatranum (Karsten). The right antapical 

 extends more or less laterally. The left antapical ex- 

 tends posteriorly a varying distance before turning an- 

 teriorly (fig. 23D). 



Variety pavlllardii (Jorgensen). The right antapical 

 is as in var. sumatranum . The left antapical is kinked at 

 the origin, and turns abruptly to the anterior (fig. 23C). 



Variety regulare n. var. The right antapical extends 

 laterally at the base but turns anteriorly. The left ant- 

 apical does not extend posteriorly, but laterally, before 

 turning anteriorly. In this respect it resembles C. 

 masslllense (fig. 23G). 



Variety reversum n. var. The right antapical is 

 kinked at the origin and turns abruptly to the anterior. 

 The left antapical extends somewhat posteriorly before 

 turning anteriorly. The curvature of the antapical horns, 

 then, is the reverse of that in var. pavlllardii (fig. 23B). 



Variety recur vum Jorgensen. The right antapical 

 begins laterally, then at about half its length turns pos- 

 teriorly. The left antapical begins posteriorly, turns 

 laterally, and then posteriorly (fig. 23A). 



Most of these varieties had the same distribution in 

 both the tropical Atlantic and Pacific oceans. Varieties 

 regulare and reversum . however, were confined to the 

 Pacific, whereas var. recur vum was common in the North 

 Equatorial Current of the Atlantic but occurred at only 

 two stations In the entire Pacific, stations 98 and 149. 



The species as a whole is intolerant tropical and 

 confined to regions of warm water. Peters (1934) found 

 C. vultur to be confined to warm, definitely oligotrophic 

 water. Nielsen (1934) found it in the Panama region and 

 the South Equatorial Current. In the Carnegie collection 

 in the Atlantic it was confined to the warm Atlantic re- 

 gion, with surface temperatures ranging from 20.°5 to 

 28.°5 C. It was found at all stations in this region except 

 one (chart 43). In the Pacific it was confined to the warm 

 Pacific and southeast Pacific regions. The surface tem- 

 peratures at the Pacific stations varied from 19.°4 (sta- 

 tion 66 in the southeast Pacific) to 29. °4 C. The ranges 

 of environmental conditions in situ were: temperature, 

 19.°8 to 29.°3 C; salinity, 29.7 to 37.1 per mille; pH, 7.76 

 to 8.42; phosphate, 2 to 189 mg P04/m3. 



It occurred at ninety-nine stations- -twenty-four in 

 the Atlantic and seventy-five in the Pacific. There were 

 251 records of occurrence, with 168 rare, 71 occasional, 

 and 12 common. Of these, 203 were net records and 48 

 were pump records. 



Nielsen (1934) foimd both the main species and var. 

 sumatranum to be shade species. The Carnegie data 

 substantiate these findings in that they show an increasing 

 frequency with Increase in depth (table 45). 



Table 45 



Records of occurrence of C. 

 at three levels 



vultur 



A=Number of records. B=Per cent of total number of 

 samples collected at that depth. 



