256 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Gonionemus pelagicus, sp. nov. 
Plate 4, Figs. 12, 13, 14. 
The bell is rounded, but low and thin. It is about twenty mm. in diameter, 
and one third as high as broad. There are about fifty long, straight, flexible 
tentacles, each of which forms a slight elbow near the tip, in the manner char- 
acteristic of the genus. These elbows, however, are so inconspicuous in life 
that the tentacles resemble Melicertum rather than Gonionemus. At the elbow 
each tentacle bears a small almost rudimentary sucking disc, and they are 
ringed throughout their whole length. At the base of each there is a cluster of 
brown pigment spots. There are sixteen otocysts. 
The proboscis is flask-shaped, nearly as broad as long. It is exceedingly 
flexible, but cannot be retracted. The mouth bears four fimbriated lips. The 
gonads, which occupy the distal third of the radial canals, consist of simple 
papilliform processes closely crowded together, as in Gonionemus murbachi, 
from Woods Holl, Mass. 
The bell is colorless: the proboscis and tentacles are yellowish green, the pig- 
ment spots at the bases of the tentacles vandyke brown, and the gonads rose 
pink. 
In life this Medusa bears little resemblance to other species of Gonionemus. | 
It swims freely by frequent contractions of the bell, the tentacles streaming 
behind at full length. The flexible tentacles are continually contracting and 
expanding and swaying to and fro in the water. The Medusa showed no incli- 
nation to attach itself, nor did it swim to the surface, sink, and then swim up 
again in the manner so characteristic of the genus. The anatomical structure 
of the tentacles also points to this habit of life, which has led me to give it the 
name “ pelagicus.” It differs from all other species of Gonionemus, to which 
genus it certainly belongs, in the rudimentary condition of the sucking discs. 
One specimen, January 7, near Gadu island, Suvadiva atoll, surface. 
Messonema coerulescens Braypt. 
Brandt, 1838, Mem. Acad. Imp. St. Pétersbourg, ser. 6, vol. 4. 
A single specimen of Messonema was taken on January 8, in Haddummati 
atoll. It probably belongs to this species, but was too fragmentary for 
accurate determination. 
Rhopalonema typicum Maas. 
Homoeonema typicum Maas, 1897, Mem. Mus. Comp. Zodl., vol. 22, p. 22, taf. 3. 
Two specimens of this species were taken on January 8, in Haddummati atoll. 
