TAXONOMY AND DISTRIBUTION 



53 



There are 5 net samples, of which 1 was taken at the 

 surface, and 2 each at 50 and 100 meters. Maximum fre- 

 quency, 82 per cent at station 158 at 100 meters; average, 

 44 per cent. 



Temperature. 27?8i-28?6o (28?i9); salinity, 35.58-35.89 

 ( 55.74); density. 22.71-23.11 (22.90); pH, 8.37-8.39 (8.38). 



Petalotricha foli Kofoid and Campbell 



(Figure 27) 

 Petalotricka joli Kofoid and Campbell, 1929, p. 204, fig. 390. 



The elongated conical lorica has a length of 2.34 oral 

 diameters. The oral margin is roughly serrate, with minute 

 points. The upper collar or shelf is a low basal segment of a 

 lull cone (90 ) with a width of less than 0.2 oral diameter 

 and with a lower diameter of nearly 0.87 oral diameter. The 

 lower collar is also a basal segment of a low, convex cone 

 (50 ) with a width of about 0.2 oral diameter and a lower 

 diameter of 0.77 oral diameter. There are sharp, optically 

 dark lines separating these two collars from each other and 

 from the bowl. The long bowl is a full cone (32 ). The 

 upper 0.16 of the bowl rounds with some suggestion of 

 shoulder which is about 0.82 oral diameter in diameter and 

 reaches 0.8 oral diameter near 0.2 total length below the 

 rim. Below this level the bowl contracts evenly, with some 

 minor local contractions and bulges, to the sharply pointed 

 but otherwise unmodified aboral end. 



The wall is subuniformly about 0.02 oral diameter in 

 thickness, and has laminae and subrectangular prisms be- 

 tween the laminae. The lower end of the bowl (about 0.4 

 total length) has irregular vertical creases or folds, and near 

 the shoulder there are circular to narrow oval lacunae in two 

 or three rows. The remaining part of the lorica is almost 

 transparent, for the small prisms do not show an external 

 meshwork. 



Length, 264 to 377H- 



There are dwarf loricae of 1.75 oral diameters scattered 

 among the larger ones, and most of the loricae tend to be 

 stouter than the figured specimen (fig. 27). 



Petalotricha joli is unlike the other species of the genus in 

 having a long, conical bowl, and in its heavy-set facies. Ap- 

 parently it spreads from off Mexico to the mid-Pacific. 



Recorded from one station (151) in the North Pacific 

 trade region, in a net sample taken at 50 meters. Frequency, 

 11 per cent. 



Temperature, i8?28; salinity, 34.42; density, 24.77; pH, 

 not recorded. 



Petalotricha major Jorgensen 

 (Figures 24, 25) 



Petalotricha major, Kofoid and Campbell, 1929, pp. 204-205, 

 fig. 384. 



The rather short lorica has a globose bowl and a length of 

 only 0.9 oral diameter. The oral margin is serrate, with 

 minute points. The upper collar is a low, almost flat shelf 

 and flares ioo°. The oral aperture has a diameter of 0.86 

 that of the outer rim of the shelf. The lower collar is a basal 



segment of an inverted truncated full cone (65 ) with a 

 diameter at its lower end of 0.7 oral diameter. The bowl is 

 globose. Its upper end is truncated where it joins the lower 

 collar, and it is 0.86 oral diameter in diameter at the maxi- 

 mum. The aboral end is smoothly rounded and without 

 differentiation. 



The thin wall is uniformly about 0.01 oral diameter in 

 thickness, and there are thin laminae with a single layer of 

 rectangular prisms enclosed. The wall is glossy gray. There 

 is a single row of tiny oval lacunae at the upper end ol the 

 lower collar where it joins the upper collar, and a belt ol 

 several rows of scattered similar ones in the equatorial region 

 of the bowl. 



Length, 95 to 1 iop. 



An extreme form is figured (fig. 25) in which a minute 

 point is present. This lorica also has a very plump bowl 

 which is considerably shorter than wide. In the same col- 

 lection were other loricae much longer than wide. The com- 

 mon form in this collection conforms to type in every detail. 

 Some loricae have a suboral curtain comparable to that of 

 P. entzi. 



Petalotricha major has a spherical bowl unlike that ol any 

 of the other species. It is quite unlike P. ampulla, in which 

 the aboral end is pointed, and it differs from P. entzi, which 

 also has a globose bowl, in that entzi has an outer hyaline 

 envelope developed around the collar. Petalotricha capsa has 

 a saccular bowl and alveoles in the wall in several layers. 



There is a possibility that P. entzi belongs to this species, 

 since specimens with the diagnostic curtain occur. If this 

 should be proved, then major becomes a synonym of entzi, 

 since Kofoid's description of the latter was much earlier than 

 Jorgensen's of major. 



Recorded from fifty-five stations, twenty-four in the At- 

 lantic and thirty-one in the Pacific, as follows: three (2, 14, 

 16) in the Gulf Stream, three (3, 4, 5) in the Atlantic drift, 

 six (17, 18, 19, 20, 20-21, 21) in the Sargasso Sea, eight (22, 

 23, 24, 25, 27, 28, 29, 30) in the Atlantic equatorial region, 

 four (31, 32, 33, 34) in the Caribbean Sea, three (46, 68, 69) 

 in the Galapagos region, four (63, 64, 65, 67) in the South 

 Pacific middle latitudes, eight (81, 82, 85, 94, 95, 96, 157. 

 160) in the region of South Pacific island fields, four (99, 

 152, 155, 156) in the Pacific equatorial region, three (100, 



150, 151) in the North Pacific trade region, two (112, 113) 

 in the North Pacific middle latitudes, and seven (131, 135, 

 136, 137, 147, 148, 149) in the California region. 



There are 15 pump and 58 net samples, of which 4 were 

 taken at the surface, 18 at 50 meters, 50 at 100 meters, and 1 

 at 150 meters. The preference of this species for subsurface 

 waters appears clear from the data. Maximum frequency, 

 86 per cent at station 30 at 100 meters; other records above 

 minimum (2 to 42 per cent) from stations 2, 3, 5, 16, 17, 18, 

 19, 20, 22, 23, 24, 27, 28, 31, 32, 33, 34, 46, 63, 65, 67, 68, 69, 



82 > 8 5> 95. 9 6 > 99. I0 °- II2 - lr 3> '3 1 - *3 6 > W> r 4 8 > x 49> r 5°> 



151, 152, 155, 156, 157, 160; averages in net samples, 16 and 

 12.3 per cent for the Atlantic and Pacific, respectively. 



Temperature: Atlantic, pump samples i4?95~20?93 (i7?4o), 

 net samples i3?79-27?88 (2i?oo); Pacific, i5?03-28?74 

 (2^47) and n?48-28?74 (2i?8i), respectively. Salinity: 



