70 MEDUSAE OF THE WORLD. 



is covered by a delicate investment of perisarc which displays a number of small annulations 

 near the upper end. The stem terminates in a single, large polypite, which is broad and 

 flask-shaped. The mouth is situated at the extremity of a tubular proboscis, and is sur- 

 rounded by a single verticil of about 16 short, flexible tentacles. In addition to these there is 

 another verticil of about 24 long, fleshy tentacles at the wide base of the polypite. These long 

 tentacles are not very contractile. They taper gradually from base to end. The tentacles 

 at the base of the polypite are about three times as long as are those surrounding the mouth. 

 The medusa-buds are borne in numbers on short, branching peduncles which arise from the 

 sides of the polypite in a zone immediately above the basal tentacles. When set free each 

 medusa has 4 short tentacles, and the 8 longitudinal rows of nematocysts upon the exumbrella 

 are well developed. The ectoderm of the stem of the hydroid is a delicate, fleshy-yellow and 

 the entodermal core is flesh-colored pink. The entoderm of the polypite is fleshy-pink and 

 yellow. 



This medusa is very common throughout the summer in Narragansett and Buzzard's 

 Bays, and on the southern coast of New England east of New Haven, Connecticut. It has 

 not been taken north of Cape Cod. It has been recorded from Beaufort, North Carolina, and 

 I found it in Winyah Bay, South Carolina, but it has not been taken either at Charleston, 

 South Carolina, or at the Tortugas, Florida. It is found in the English Channel and off the 

 North Sea coasts of England, Scotland, Holland, and Germany. As in America, it appears to 

 be abundant only in a few localities. I found several specimens of this medusa in the English 

 Channel in October, 1907, and they appear to be identical in all respects with medusx from 

 the southern coast of New England, in America. Hargitt has recently discovered the hydroid 

 at Woods Hole, Massachusetts. 



Ectopleura minerva Mayer. 

 Plate 5, fig. 3. 



Ectopleura, sp., FEWKES, 1883, Bull. Mus. Comp. Zool. at Harvard College, vol. II, p. 85, plate I, fig. n. 



Ectopleura minerva, MAYER, 1900, Bull. Mus. Comp. Zool. at Harvard College, vol. 38, p. 31, plate 16, fig. 38; plate 37, fig. 125. 



( ?) Ectopleura dumortieri, GRAEFFE, 1884, Arbeit. Zool. Inst. Wien, Bd. 5, p. 354. 



This medusa has 2 well-developed and 2 rudimentary tentacles, instead of 4 equally 

 developed tentacles as in the northern species of Ectopleura. 



Bell 2.5 mm. high and pear-shaped, with a well-developed apical projection. Bell-walls 

 of moderate thickness. 8 rows of nematocyst-cells extend from the 4 tentacle-bulbs to the 

 apex of the bell. There are 2 well-developed tentacles and 2 small tentacle-bulbs. There 

 are 6 to 9 separate wart-like swellings upon the outer side of each of the 2 large tentacles. 

 These swellings are crowded with nematocysts. Basal bulbs of tentacles small and without 

 ocelli. There are 4 straight, narrow radial-canals and a slender, circular vessel. The velum 

 is well-developed. Manubrium pear-shaped and about two-thirds as long as the depth of the 

 bell-cavity. It is wider near the middle than at either end. The mouth is a simple, round 

 opening. A simple, short, conical style-canal extends upward into the apical projection of 

 the bell. 



The entoderm of the manubnum and tentacles is a delicate purple, while the supporting 

 lamella of the bell is of a decided green. There are a large number of brilliant yellow spots 

 in the entoderm of the radial-canals and tentacle-bulbs. 



This form is rare at Tortugas, Florida. It was found by Fewkes at the Bermudas. A 

 similar medusa was described by GraefFe, 1884, from Trieste, Mediterranean, under the name 

 Ectopleura dumortieri. 



Ectopleura minerva may prove to be identical with E. pacifica Thornely, from the tropical 

 Pacific. 



Ectopleura pacifica Thornely. 



Eclopleura pacifca, THORNELY, 1900, Zool. Results, A. Willey, Part 4, p. 452, plate 44, figs, i, la, Cambridge, England. 



Hydroid. Stems simple, unringed, diminishing in width toward the base, and 20 mm. 

 high, rising from a creeping stolon which connects the colony. Some of the stems give rise 

 to stolons near their bases. The polypite is abruptly marked off from the supporting stalk. 



