ANTHOMEDU&E NEMOrSIS. 17.'! 



Favonia and his briet and unsatisfactory description are only confusing. It is evident that the 

 figure is very erroneous, and it appears to hear a closer relationship to I.\'ni<i>,-<i than tn 

 Nfinrjpsis. No marginal tentacles are shown, and the flat, hell-shaped disk is wholly unlike 

 any known species of Nemopsis. 



favonin octonfma Peron et Lesueur is probably an imperfect specimen of some species 

 of Lymnorea. Haeckel calls this "Nemopsis favrjnin." 



I can distinguish no difference between HaeckiTs A', -WO/MM " li,-t,-i nnnnn " and A'. 

 />iii-lii-i ot our coast. It was described from an isolated specimen found on the coast of \<>i- 

 way, and falls within the common limits of variability of N. bachci in all respects. It is 

 possibly an individual which may have drifted across the Atlantic in the trend of the winds 

 and currents. 



The genus Nftnnpsis is evidently derived from the more generali/.ed l}nn!'<iiii;-illi-i in 

 which the marginal tentacles have become speciali/.ed into two sorts and the 4 radial corners 

 of the stomach have extended far outward along the radial-canals. The hydroid remains 

 identical with that of Bougainvillia. 



Nemopsis is one of those exceptional Anthomedusae in which the gonads have migiati-d 

 outward from the sides of the stomach along the radial-canals. J)i>Min,'in,i among the Tiariiue 

 is another instance ot the same sort. In the medusa; we frequently find that the hard and fast 

 distinctions which Haeckel attempts to apply to the separation of families do not hold in 

 nature. Thus the gonads are often more or less interradial in the Codonidae, or more or less 

 upon the sides of the manubrium in the Thaumantiada;; the lithocyst-bearing medusa l:ntn>i,i 

 arises from a hydroid having the superficial appearance of one of the Tubularian order, and 

 Rntlikca fascicultita is the only medusa of the Oceanidae with 4 frrr/iJinl gonads. 



Nemopsis bachei L. Agassiz. 



Plate 17, figs. 5 anil 6. 



Ncmopsn bachei, AGASSIZ, L., 1849, Mem. Amer. Acad., New Scries, vol. 4, p. 289, i fig. 1862, Cont. Nat. Hist. I . s., 

 vol. 4, p. 345. AGASSIZ, A., 1862, Proc. Boston -Soc. Nat. Hist., vol. 9, p. 98, figs. 26, 27. 1865, North Amir. A. ll., 

 p. 14*), figs. 227-231 . VKRRILL, 1873, Report Commis. Fish and Fisheries U.S. for 1871-72, pp. 454, 733- HAF< KM, 

 1879, Syst. der Medusen, p. 93. BROOKS, 1883, Studies Johns Hopkins Univ. Biol. Lab., vol. 2, p. 468 (hvdrmd and 

 young medusa). BROOKS, 1890, Handbook of Invert. Zoo]., p. 40, fig. 21. NI'TTING, 1901, Bull.U. S. Fish Cnmmis- 

 sion for 1899, vol. 19, p. 375, fig. 88. HARGITT, 1904, Bull. U. S. Bureau of Fisheries, vol. 24, p. 41, I fig.; 1901 , Ameri- 

 can Naturalist, vol. 35, p. 583, fig. 47; 1901, Biol. Bulletin, Woods Hole, vol. 2, p. 227. 



Vfinnftsi! gibbuii, McCfiADV, 1857, Gymn. Charleston Harbor, p. 58, plate 10, figs. 1-3, non figs. 4-7. 



Favonia bachei, HAECKF.L, 1877, Prodrom. Syst. Medusen, No. 103 (unpublished). 



.Vemopsis heirronema, HAF.CKEL, 1879, Syst. der Medusen, p. 93, taf. 5, fign. 6-9 (isolated specimen from coast of Norway). 



Adult medusa (plate 17, fig. 6). Bell about II mm. high, being higher than a hemi- 

 sphere, with relatively straight sides and flat top. There are 4 radially situated clusters ot 

 marginal tentacles. Each cluster arises from a cleft, pad-like base and contains about 14 

 tentacles. The median pair of tentacles are short, slender, and terminate each in a knob- 

 like cluster of nematocysts (plate 17, fig. 5). These median tentacles are flanked by a long, 

 highly contractile pair which contain reddish-brown pigment in their ectoderm. On either 

 side of these brown tentacles there are 5 transparent, highly contractile, filiform tentacles. 

 When swimming the medusa often carries its tentacles with their shafts extending straight 

 outward at an acute angle with the sides of the bell, while the extremity ot each tentacle bends 

 sharply downward at a right angle, recalling the appearance presented by the tentacles ot 

 Gonionemus. There is a dark-colored ectodermal ocellus at the base of each tentacle on the 

 lower (velar) side. The bell-cavity is about three-quarters as deep as the bell-height. There 

 are 4 straight, narrow radial-canals and a slender circular vessel. The velum is well developed. 

 The gonads are flat and ribbon-like, with curtain-like folds, and they extend down the radial- 

 canals, along the sides of the 4 stomach-pouches, which project about two-thirds the distance 

 from the sides of the manubrium to the tentacle-bulbs. The manubrium is short, with 4 

 simple, quadratic lips, and with 4 radially situated clusters of oral tentacles. Each of these 

 oral clusters arises from a single shaft which bifurcates from 5 to 7 times, terminating in 32 

 to 128 small, nematocyst-covered knobs. The entodermal cores ot the oral tentacles consist 

 of chordate cells. Gonads, stomach, and tentacle-bulbs dull milky-yellow to orange. This 



'4 



