LEPTOMEDUS^E — EUCHEILOTA. 283 



bearing cirri. In addition to these there are normally about 8 other cirri in each quadrant, and 

 scattered between them are 8 lithocysts. Thus the medusa has 32 lithocysts and 48 cirri. Each 

 lithocyst is of small size and contains a single spherical concretion. The velum is well devel- 

 oped. There are 4 straight, narrow radial-canals and a simple circular vessel. The manubrium 

 is short but wide, and there are 4 cruciform, slightly recurved lips. There is no peduncle. The 

 4 gonads are found upon the 4 radial-canals near the manubrium. These are visible in young 

 medusa; about 1.5 mm. in diameter; and in the adult they become quite large and swollen, the 

 ova being distinctly seen lying along the side of the canal. The entoderm of stomach, gonads, 

 and tentacle-bulbs is grass-green, and the supporting lamella of the bell is tinged with the 

 same color. 



This medusa was quite common at the Tortugas, Florida, from June 17 to 25, 1899. 

 Fewkes found it at Bermuda. 



Toung medusa. — The youngest medusa seen by me was about 2 mm. in height and 1.5 

 mm. in diameter. It was nearly in the condition described by Fewkes, 1883. There were 4 

 simple, radially situated tentacles and 4 interradial tentacle-bulbs. The interradial tentacle- 

 bulbs were flanked by lateral cirri, while the radial tentacle-bulbs lacked these appendages. 

 There were 4 lithocysts, one upon the side of each of the interradial tentacle-bulbs. Each litho- 

 cyst contained a single spherical concretion. The gonads were already quite large, and lay 

 along the 4 radial-canals near the sides of the manubrium. The manubrium is short with 

 4 simple lips. 



Eucheilota duodecimalis A. Agassiz. 

 Plate 36, fig. 6; plate 37, figs. 1 and 2. 



Eucheilota duodecimalis, A. Agassiz in L. Agassiz's, 1862, Com. Nat. Hist. U. S., vol. 4, p. 353— Agassiz, A., 1865, North Ameri- 

 can Acalephs, p. 75, figs. 106-1070. — Nutting, 1901, Bull. U. S. Fish Commission, vol. 19, p. 378, fig. 95, a, b.— Hargitt, 

 1904, Bull. U. S. Bureau of Fisheries, vul. 24, p. 46, plate 4, fig. 3. 



Phialium duodecimale, Haeckel, 1879, Syst. der Medusen, p. 180.— Fewkes, 1882, Bull. Mus. Comp. Zool. at Harvard College, 

 vol. 9, p. 297, plate 1, figs. 17-21. 



Phialium dodecasema, Haeckel, 1879, Syst. der Medusen, p. 181. 



Phialium duodecimalis, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 154, plates 6 and 38. 



Adult medusa. — Bell slightly higher than a hemisphere, about 2.5 mm. in diameter; bell- 

 walls quite thin, no thicker at apex than near the margin. There are 4 long, slender, radially 

 situated tentacles with large basal bulbs and lateral cirri; lateral cirri short and covered with 

 nematocyst-cells. Each tentacle-bulb is flanked by 2 cirri. There are 12 lithocysts, 3 in each 

 quadrant. Each contains a single spherical concretion. Velum well developed. There are 4 

 straight, narrow, radial tubes, and a slender, circular vessel. Manubrium very short and 

 square in cross-section. The gonads are developed upon the outer halves of the 4 radial-canals. 

 Ova of female large and prominent. 



The entodermal lamella of the bell displays a decided green tinge. The entoderm of the 

 stomach, gonads, and tentacle-bulbs is of a decided yellow-green. 



Young medusa. — In the smallest medusa observed the diameter of the bell was 1 mm. 

 There were 4 tentacles, but 2 of them were much more developed than the others. There were 

 only 4 lithocysts, one in each quadrant. The gonads had begun to develop upon the radial- 

 canals very close to the circular vessel. 



This medusa is very common upon the southern coast of New England, at Newport 

 Harbor, Rhode Island, and Buzzard's Bay, Massachusetts. A single specimen was found in 

 Charleston Harbor, South Carolina, in 1898; and at Tortugas, Florida, in June, 1902. The 

 medusa makes its appearance at Newport in July and continues to be abundant until the last 

 week of September. Bigelow has found this medusa in Acapulco Harbor, on the west coast 

 of Mexico. 



