282 MEDUS.E OF THE WORLD. 



GENERIC CHARACTERS. 



Eucopidae with 4 or more small, closed, vesicular lithocysts, each containing 1 or more 

 concretions. There are lateral or marginal cirri or hoth. The gonads are developed upon the 

 4 radial-canals. There is no peduncle. The hydroid is Campanulma{ ?) 



The species of this genus vary greatly in the number of lithocysts and tentacles. In fact, 

 were we to attempt to classify them according to the number of these structures it would be 

 necessary to erect a separate genus for each one of the known species, as has practically been 

 done by Haeckel, 1879. I believe, therefore, that generic distinctions based upon the number 

 of lithocysts and tentacles are of no value in the classification of these species. Among the 

 known species of Eucheilota the lithocysts vary from 4 to 32 and the tentacles from 4 to 30. 



The genus Eucheilota, as we define it, consists of Eucopidae with small, closed lithocysts, 

 while in Mitrocoma the lithocysts are open sacs containing usually a large number of concre- 

 tions. Both of these genera possess marginal and lateral cirri and are very closely related. 



Eucheilota paradoxica is remarkable in that it develops medusa-buds upon its gonads. 

 These budding medusas are developed from both ectoderm and entoderm of the parent gonad, 

 both layers taking their proportionate share in the formation of the daughter medusa as in 

 Sarsia or in hydroids generally. Such budding of medusae is common in Anthomedusae, but 

 exceedingly rare in Leptomedusae. 



Eucheilota ventricularis McCrady. 

 Plate 37, fig. 5; plate 38, figs. I to 1". 



Eucheilota ventricularis, McCrady, 1858, Gymn. Charleston Harbor, p. 85, plate 11, figs. 1, 2; plate 12, figs. 1-3. — Agassiz, L., 

 1862, Cont. Nat. Hist. U. S., vol. 4, p. 353. — Agassiz, A., 1862, Proc. Boston Soc.Nat. Hist., vol. 9, p. 94, figs. 16, 17.— 

 Fewkes, l88l,Bull.Mus.Comp.Zool. at Harvard College, vol. 8, No. 8, p. 159, plate 5, figs. 7-10.— Brooks, 1882, Studies 

 Johns Hopkins Univ. Biol. Lab., vol. 2, p. 139. — Hargitt, 1904, Bull. U. S. Bureau of Fisheries, vol. 24, p. 46, plate 

 4, fig. 4. — Mayer, 1900, Bull. Museum Comp. Zool. at Harvard College, vol. 37, p. 55, plate 38, fig. 128. 



Euchilota ventricularis, Agassiz, A., 1865, North American Acalephse, p. 74, figs. 104, 105. — Haeckel, 1879, Syst. der Medusen, 

 p. 179. 



Bell hemispherical, 10 mm. in diameter. 16 well-developed tentacles with long, tapering, 

 hollow, basal bulbs; each tentacle-bulb is flanked by a pair of short cirri. Besides the large 

 tentacles there are 16 small projections on the bell-margin, each flanked by a pair of cirri, and 

 about 24 very minute projections not flanked by cirri. 8 lithocysts, 2 in each quadrant and each 

 containingabout 8 spherical concretions arranged in a half circle. Velum well developed. There 

 are 4 straight, narrow radial-canals and a slender, circular vessel. Manubrium is short and 

 quadratic, provided with 4 prominent recurved lips. The gonads are linear and are found in 

 the middle regions of the radial-canals, each gonad being about one-third as long as the canal 

 upon which it is situated. In the female the eggs project from the surface of the ectoderm of 

 the gonads. 



The entoderm of the stomach, gonads, and tentacle-bulbs is a decided green. 



During the summer and autumn this medusa has been found in Hampton Roads, Vir- 

 ginia; at Beaufort, North Carolina; Charleston, South Carolina; and Tortugas, Florida. It 

 is rare on the southern coast of New England and is probably only occasionally carried there 

 by the northerly drift from the Gulf Stream. 



In the young medusa the bell is higher than a hemisphere. There are 4 radially situated 

 tentacles with lateral cirri. The gonads do not develop until the medusa has attained a con- 

 siderable size. 



Eucheilota bermudensis Mayer. 



Plate 37, fig. 4; plate 38, figs. 2, 3. 



Oceanopsis bermudensis, Fewkes, 1883, Bull. Museum Comp. Zool. at Harvard College, vol. II, p. 86, plate I, figs. 8-IO. 

 Eucheilota bermudensis, Mayer, 1900, Bull. Museum Comp. Zool. at Harvard College, vol. 37, p. 56. 



Adult medusa (plate 38, fig. 3). — Bell not quite hemispherical, the sides being relatively 

 straight and sloping and top quite flat. It is about 6 mm. in diameter. 8 tentacles, 4 radial 

 and 4 interradial; tentacles only about a third as long as bell-diameter, and thickly covered 

 with nematocysts; their basal bulbs large, each flanked by a pair of short, coiled, nematocyst- 



