40 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



neiuatocyst cells. Medusa buds arise from the sides of the gastric portion of 

 the proboscis. When set free each medusa possesses 4 short equally developed 

 tentacles. The entoderm of the proboscis is usually red in color, although 

 sometimes the inner core is red or pink and the outer annulus is green. Each 

 tentacle bulb is provided with a dense mass of red entodermal pigment, which 

 in the case of the radial tentacles extends for a considerable distance up the 

 course of the radial canals. 



Young Medusae. — The youngest medusa found free in the water was 1.5 

 mm. in height (Figure 124), and the bell was about twice as high as it was 

 broad. The gelatinous substance was quite thin. There were only 4 mar- 

 ginal tentacles and these were radial in position. The distal tips of these ten- 

 tacles were slightly knobbed and their entoderm was tinged with green. There 

 were 8 simple oral tentacles, and the proboscis lacked a peduncle. In an 

 older individual, which was 2.5 mm. in height, the bell was pyriform. The 

 proboscis possessed a peduncle, and there were 8 marginal tentacles, 4 radial 

 and 4 interradial. There were no traces of medusa buds upon tlie proboscis. 



This medusa was quite common at the Tortugas, Florida, about the middle 

 of June, 1899. 



DYSMORPHOSA, Philippi, 1842. 

 Dysmorphosa dubia, nov. sp. 



Figs. 64-66, Plate 23. 



Specific Characters. — The bell is egg-shaped and 1.5 mm. in height. The 

 bell walls are thin and flexible. There are 8 quite stiff tentacles (Figure 66) 

 that are carried curled slightly upward. The distal ends of these tentacles are 

 thickly covered with nettling cells. A very large black ocellus is situated in 

 the ectoderm of the under side of each tentacle bulb. The velum is well 

 developed. There are 4 straight, narrow, radial tubes ; and a slender circular 

 canal. The proboscis is pear-shaped, and there is a slightly developed peduncle. 

 4 radially situated oral tentaculse surround the mouth. Each one of these 

 terminates in a knob-like cluster of nematocysts (Figure 65). 4 small, rudi- 

 mentary gonads? appear to be developed at points midway along the lengths of 

 the 4 radial canals. The entoderm of the proboscis, tentacle bulbs, and gonads ? 

 is of a delicate yellow. One specimen was found at the Tortugas, Florida, 

 on July 20, 1898. 



The presence of what appear to be gonads ? upon the radial tubes is certainly 

 remarkable ; it should be remembered, however, that such appearances are not 

 unknown among genera of Tubularian medusae that normally bear their gonads 

 upon the proboscis. In the case of Dipurena halterata bodies that are very 

 similar in general appearance to rudimentary gonads are found upon the 

 radial canals. (See Forbes, E., 1848, British Naked-Eyed Medusre, p. 53, 

 Plate VI., Figures 1, b, c, d. Also Browne, E. T., 1898, Proc. Zool. Soc. 

 London, p. 816, Plate 49, Figure 2.) 



