LEPTOMEDUSjE — PHORTIS. 307 



Genus PHORTIS McCrady, 1857. 



Phortis, McCrady, 1857, Gymn. Charleston Harbor, p. 90. — Brooks, 1883, Studies Johns Hopkins Univ. Biol. Lab., vol.2, 

 p. 470 (hydroid and medusa). 



This genus was founded by McCrady, 1857, for Phortis gibbosa of the southern Atlantic 

 coast of the United States. 



GENERIC CHARACTERS. 



Eucopidae with numerous lithocysts and numerous simple tentacles. There are neither 

 lateral nor marginal cirri. The 4 gonads are developed upon the 4 radial-canals. The stomach 

 is mounted upon a well-developed peduncle. The hydroid is Phortis Brooks, 1883. 



This genus is very closely related to Eirene and to Tima of Eschscholtz, 1829, but differs 

 from them in having neither marginal nor lateral cirri. Bigelow, igog, merges it with 

 Eirene. 



Phortis gibbosa McCrady. 



Non Eirene gibbosa, Eschscholtz, 1829, Syst. der Acal., p. 94. 



Phortis gibbosa, McCrady, 1857, Gymn. Charleston Harbor, p. 91. 



Eirene gibbosa, Agassiz, L., 1862, Cont. Nat. Hist. U. S., vol. 4, p. 362. — Acassiz, A., 1865, North Amer. Acal., p. 112. 



Irene gibbosa, Haeckel, 1879, Syst. der Medusen, p. 203. 



Phortis gibbosa, Brooks, 1883, Studies Biol. Lab. Johns Hopkins Univ., vol. 2, p. 470. 



Adult medusa. — Bell about 25 mm. in diameter. Somewhat higher than broad, its out- 

 line that of a paraboloid of revolution. There are about 60 long slender tentacles with large 

 basal bulbs. No cirri upon sides of tentacles or upon bell-margin; about 60 lithocysts alter- 

 nate with the tentacles; each usually contains a single spherical concretion. There are 4 

 straight, narrow, radial tubes. The manubrium is provided with a wide peduncle, which 

 fills the greater part of the bell-cavity, but it is not very long and does not quite extend to the 

 level of velar opening. Stomach quite large, projecting beyond velar opening. Gonads linear 

 and developed upon outer parts of radial-canals between base of peduncle and bell-margin. 

 ! Entoderm of gonads and tentacle-bulbs reddish in color. 



Hydroid and young medusa. — Brooks, 1883, describes 



4. the hydroid stock and young medusa of this species. The 



hydroid was found at Beaufort, North Carolina, attached to 



stems of Aglaophenia. A long, slender stolon, or hydrorhiza, 



runs along the stem of the Aglaophenia and gives rise, at 

 quite regular intervals, to short, annulated branches, some ter- 

 minating in hydranths and others in reproductive calycles, 

 which do not differ much from the hydrothecae either in size or 

 shape. Hydrothecae are trumpet-shaped, slightly curved, taper- 

 ing gradually from the base to the wide, flaring, reflected opening. The polypites are long 

 and slender, and have about 12 tentacles with rings of lasso-cells. The reproductive calycles 

 are very similar in size and shape to the hydrothecae. The reproductive calycle, however, 

 tapers somewhat more gradually toward the pedicel than does the hydrotheca. Annulations 

 run up for half its length or more, and its distal end is less flaring than the hydrotheca. The 

 blastostyle runs along one side of the reproductive calycle and terminates in a club-shaped 

 tip. 3 or 4 medusa-buds develop upon one side of the blastostyle, the oldest being at the 

 distal end. Only one medusa escapes at a time. When set free the exumbrella of the medusa 

 is regularly curved and its height is a little greater than its diameter. The subumbrella, on the 

 other hand, is bent upon itself about half-way up, at an obtuse angle, and the lower or free 

 half of the umbrella is about twice as thick as the upper half. The manubrium is very short 

 and consists of an upper, flat, gastric part which extends outward along the 4 radial tubes for 

 about a sixth of their length, and a mouth-tube about a fifth the height of the umbrella. 

 The mouth-tube is provided with 4 well-developed cruciform lips. The young medusa 

 possesses 10 tentacles, arranged as shown in the diagram. (1, 1) are well developed and are 

 about two or three times as long as the bell-diameter; (2) is shorter, and (3) is still more 

 undeveloped; (4, 4, 4, 4) are mere rudimentary tentacle-bulbs, and (5, 5) are still smaller. 

 None of the tentacles have lateral cirri. There are no lithocysts in the very young medusa?. 



