238 BULLETIN OF THE 



manubrium there was an oval-shaped, green ectodormal pigment spot. The four 

 lips of the manubrium were very distinct in cross-section, standing off from one 

 another like the four arms of a Swiss cross. There were twenty-four large, 

 stiff, club-shaped tentacles about as long as the height of the bell, and also 

 twenty-four short cirrus-like tentacles lying between the large ones. 



The large tentacles were girdled at regular intervals by rings of nematocyst 

 cells. In a state of partial contraction they showed a globe-like swelling near 

 the distal end, terminated by the shrunken cap-like end of the tentacle. 

 The smaller tentacles exhibited only a simple terminal bunch of nematocysts. 

 The entoderm of the basal bulbs of all the tentacles was colored claret-purple, 

 and there was also a green ectodermal ocellus-like spot upon the ventral sur- 

 face of each bulb. These were similar in color to the green spots upon the 

 manubrium. The entodermal core of all the tentacles was of a claret-purple 

 color. There were twelve elongated spindle-shaped otocysts (see Plate II. 

 Fig. 3) between the tentacles, three in each interradius. In each of these oto- 

 cysts there was an oval cavity containing a highly refractive spherical otolith. 

 It is remarkable that in this Medusa we find both otocysts and pigment spots ! 

 The animal was very vigorous in all its movements, and remarkably tenacious 

 of life in captivity. 



Ireniopsis primordialis, nov gen et sp 



Plate I. Figs. 3, 4, 5, 6. 



Three stages of another curious Hydro-Medusa were found in surface tows 

 made early in March while upon the Little Bahama Bank. It is closely allied 

 to Cubaia Aphrodite, described above, but we prefer to place it in another 

 genus, owing to the dissimilarity in shape of the otocysts, the greater develop- 

 ment of the peduncle, and certain minor differences in the disposition and 

 growth of the tentacles, which will be explained more in detail further on. The 

 name Ireniopsis primordialis is proposed for it. 



The youngest specimen (Plate I. Fig. 5) possessed a transparent, thimble- 

 shaped bell 1 mm. in height. The outer surface was scattered over with 

 rather regularly spaced nettle capsules. The ectoderm of the cavity of the bell 

 was of a delicate shade of pea-green. There were four simple radial canals. 

 The manubrium, in this stage of its development, was very small, with four 

 distinct lips. It was green in color. There was, as yet, no trace of the pe- 

 duncle of the manubrium. There were sixteen tentacles and only four otocysts 

 in the specimen examined. The otocysts were spherical sacs enclosing a cavity 

 within which there was a very refractive otolith. The tentacles exhibited regu- 

 larly spaced rings of nematocyst cells. At the bases of the tentacles there was 

 an accumulation of green pigment. 



An older individual than the above (Plate T. Fig. 3) was found near Burrow 

 Cay, March 8th. The bell had widened out and was 1.6 mm. high, and the 

 nettle cells over its outer surface were much less conspicuous than in the young 

 specimen. The manubrium began to show a slight trace of a peduncle. The 



