144 EXPEDITION OF THE "ALBATROSS," 1899-1900. 



of this medusa was obtained, in an open net towed between 300 fathoms 

 and the surface, off Marokau Island, Paumotus Group. 



(300 i—S) J ; Station 136; October 28, 1899; S. Lat. 18° 08', VV. Long. 141° 49'. 



Lymnorea ocellata, sp. nov. 



Plate 2, figs. 9-12. 



The top of the bell is flat and the sides flare outward in a bell-shaped 

 manner. The animal is about 4 mm. in diameter, and is about as high 

 as it is broad. The bell-walls are thin, and quite flexible. There are 

 about fifty short stiff tentacles which are each about one-half the length of 

 the bell-height. These tentacles are usually carried curled upward, and 

 their entodermal cores are solid and composed of vacuolated chordate 

 cells. The basal bulbs of the tentacles are large, and each one contains 

 a mass of red pigment. In addition to this there is a prominent ectoder- 

 mal ocellus upon the ventral (lower) side of each tentacle at a short 

 distance centrifugally from the basal bulb. The velum is small. There 

 are four straight, narrow radial canals and a slender circular tube. The 

 peduncle of the proboscis is wide and quadratic in cross-section, and its 

 lower portion, near the gastric region, consists of highly vacuolated ento- 

 dermal cells. The gastric part of the proboscis is pear-shaped, and the 

 mouth is a simple round opening. The entire proboscis extends about 

 one-half the distance from the inner apex of the bell-cavity to the level 

 of the velar opening. There are four well developed oral tentacles, each 

 one of which is about half as long as the height of the proboscis. Each oral 

 tentacle branches dendritically four times, thus giving rise to sixteen distal 

 knobs. Each knob is thickly covered with a bristling cluster of fusiform 

 nematocyst cells. In addition to these there are several patches of nema- 

 tocystic bristles upon the sides of the main trunk of each oral tentacle. 

 The gonads are developed in four radial regions within the gastric part 

 of the proboscis. The entoderm of the tentacle bulbs and of the gastric 

 part of the proboscis is brick-red. The ectodermal ocelli are black. A 

 number of these medusas were obtained on the surface in the lagoon of 

 Makemo Island, Paumotus, on October 23, 1899. 



