1138 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Record of Hawaiian specimens. 
No. of 
speci- 
mens. 
Date. 
Station. 
Geographical position. 
Depth. 
Remarks. 
1902. 
Fathoms. 
4 
June 17 
4005 
Ukula Point, Kauai Island. . . 
577-480 
One small specimen 55 mm. high, 50 mm. wide. No 
gonads. Figured. Three large specimens about 
100 mm. wide, 70 mm. high. With gonads. One 
figured. 
1 
June 24 
4029 
do 
478-453 
Medium size, about 45 mm. wide, 45 mm. high. 
Damaged. 
P. dodecabostrycha is widely distributed over the floor of the deep oceans, especially in tropical 
regions of the Pacific. It has been found off the west coast of Mexico, off the coast of Chile, in the 
Indian Ocean, in the Malay Archipelago, even in the Guinea Stream, off the west coast of Africa, by 
the Valdivia, and in the Mediterranean, by the Prince of Monaco. 
In small specimens a short, usually curved, diverticulum of the gastro-vascular space extends 
upward into the gelatinous substance of the apex of the bell. As was suggested by Vanhoffen, this 
may indicate that the medusa develops through an alternation of generations. This canal appears in 
our figure 5, plate n of the young medusa. Unfortunately we know nothing of the development of 
the Periphyllidse. 
Genus ATOLLA Haeckel. 
Atolla, Haeckel, Syst. der Medusen, p. 488, 1880. Fewkes, Report U. S. Commis. Fish and Fisheries for 1884 
(1886). Vanhoffen, Ergeb der Deutschen Tiefsee-Expedition, bd. 3, 1902, p. 22 etc. Maas, Result. Campagnes 
Sci., etc., Prince de Monaco, fasc. xxvm, 1904, p. 48. 
Generic characters: Collaspidte with numerous (16 or more) tentacles which alternate with an 
equal number of marginal sense organs. The marginal lappets are twice as numerous as the tentacles, 
or marginal sense organs. The pedalia of the tentacles arise from a zone higher up upon the sides of 
the exumbrella than do the pedalia of the sense organs. 
Atolla alexandri Maas. 
PI. Ill, figs. 10, 11; PI. II, fig. 7. 
Atolla alexandri Maas, O., Mem. Mus. Comp. Zool., vol. xxm, 1897, p. 81, taf. xi, fig. 2, taf. xiv, figs. 4, 6. Agassiz 
and Mayer, ibid., vol. xxvi, 1902, p. 156. 
Four specimens of Atolla, all belonging to the species alexandri, were found by the Albatross, and 
we present life-size drawings of the largest specimen. 
In A. alexandri we find, occupying the center of the exumbrella, a smooth-edged lenticular-shaped 
disk. This raised central portion of the exumbrella is about one-half as wide as the medusa itself. 
Thus in a medusa 64 mm. wide the central convexity is 33 mm. wide. The outer edge of this raised 
center is smooth, simple, and annular, and wholly lacks the radial folds and furrows seen in other 
species of Atolla. A deep annular groove encircles the outer edge of the central disk. Immediately 
beyond this groove lies the zone of tentacular pedalia. In a medusa 64 mm. in diameter these pedalia 
are each 5.5 mm. wide, and each one of them supports a short tapering tentacle about 13 mm. long. 
These pedalia are partially separated one from the other by deep radial clefts which extend radially 
inward midway between the tentacles for about one-half the distance from the outer edges of the 
pedalia to the annular furrow. In-a medusa 64 mm. wide there were 32 pedalia and the same number 
of tentacles. Intermediate and alternating with the pedalia are the bases of the lappets. These lappet- 
stalks arise at a level lower than the pedalia of the tentacles, and each one bears a single marginal 
sense organ flanked by a pair of elongate marginal lappets. The sense organs, tentacles, and tentacular 
pedalia are thus equal in number each to each, while the marginal lappets are twice as numerous. 
Thus in the medusa 64 mm. in diameter there are 32 pedalia, 32 tentacles, 32 marginal sense organs, 
and 64 marginal lappets (see fig. 11). 
Turning now to the subumbrella side of the medusa, we find at the center a more or less miter- 
shaped dark-colored manubrium, at the extremity of which we find the mouth surrounded by 4 long, 
narrow tapering lips. (See fig. 10, pi. iii. ) 
