TRACHYMEDUS.E — GERYONIA. 425 



Geryoma is the host of the parasitic larvae of Cunina, and as such has been made the special 

 stud)' of Metschnikoff, Maas, Woltereck, StschelkanowzefF, and others. 



Geryonia proboscidalis Eschscholtz. 

 Plate 53, figs. I to 3; plate 54, fig. 10. 



Medusa proboscidalis, Forskal, 1775, Rescript, animalium Haunia?, p. 108; Icon., tab. 36, fig. I. 

 Dianaa proboscidalis, Delle Chiaje, 1822, Mem. Anim. senza Vert., Regno Napoli, tav. 73, fig. 9. 

 Geryonia proboscidalis, Eschscholtz, 1829, Syst. der Acalephen, p. 88. — Leuckart, 1856, Archiv. fur Naturgesch., Jahrg. 22, 



p. 8, taf. 1, fig. 3. — Gegenbaur, 1856, Zeit. fur wissen. Zool., Bd. 8, p. 254, taf. 8, fig. 16. — Noshin, 1865, Melang. 



biolog. St. Petersbourg, tome 5, p. 28, plate I (development). — Metschnikoff, E., 1886, Arbeit. Zool. Inst. Mien, Bd. 



6, p. 247; 1886, Embryol. Studien an Medusen, Wien, pp. 23 (egg), 59 (formation of entoderm), 91 (development of larva 



and medusa), taf. 6, fign. 4-12. — Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Dampfer Valdivia, Bd. 



3, Lfg. 1, pp. 84, 85, taf. 10, fig. 15. — Bigelow, H. B., 1909, Mem. Museum Comp. Zool. at Harvard College, vol. 37, 



p. 1 16. 

 Geryonia hexaphylla, Brandt, 1838, Mem. Acad. Sci. St. Petersbourg, p. 389, taf. 18. — Schulze, 1875, Mittheil. Naturw. 



Vereins fur Steiermark, p. I, taf. 1. — Maas, 1897, Mem. Museum Comp. Zool. at Harvard College, vol. 23, p. 26, taf. 



3, fig. 6. 

 Liriope proboscidalis. Lesson, 1843, Hist. Zoopb. Acal., p. 331. 



Geryonia proboscidalis + I.euckartia proboscidalis, Agassiz, L., 1862, Cent. Nat. Hist. U. S., vol. 4, p. 364. 

 Geryonia hastata, Haeckel, 1864, Jena. Zeitsch. fur Naturw., Bd. I, p. 467, taf. 1 1; Bd. 2, p. 143, taf. 5, 6. 

 Geryonia jungijormis, Fol, 1873, Jena. Zeitsch. fiir Naturwissen., Bd. 7, p. 472, taf. 24, 25 (development). 

 Geryonia proboscidalis-^- G. dianaa+ ( ?) Carmaris umbella+ Car mar is gihschii-¥ Carmarinahastata+ C.jungijormis-¥ C. hexaphylla, 



Haeckel, 1879, Syst. der Medusen, pp. 295-298, taf. 18, fig. 8. 

 Carmarina hastata, Krukeneerg, 1880, Vergleichend. physiolog. Studien zu Tunis, Mentone und Palermo, Abth. 3, p. 124, etc. 



(reactions to curare and strychnine). — Sanzo, 1903, Archiv. Italiennes de Biologie, tome 39, p. 318 (the process of 



inhibition in the rhythmical pulsation). — Bethe, 1903, Allgemeine Anat. und Physiol. Nervensyst., pp. 411, 414, 415, 



419, etc., fig. 83c; 1908, Pfliiger's Archiv., Bd. 124, p. 451; Ibid., 1909, Bd. 127, p. 219 (laws of pulsation). — Maas, 



1908, Verhardl. deutsch. Zool. gesell, p. 116 (experimental embryology). 

 Geryonia (Carmarina) jungijormis, Mftschnikoff, E., 1881, Zeit. fur wissen. Zool., Bd. 36, p. 433, taf. 28, fig. 1-4 (develop- 

 ment). 

 Carmarina hastata, Schneider, 1891, Zool. Anzeiger, Bd. 14, p. 379 (histology of nettle-cells); 1892, Jena. Zeit. fiir Naturwissen., 



Bd. 20, p. 423, taf. 14, fign. 21-39, 4 2 "4^ (histology of nervous system, nematocysts, etc.) — Nagel, 1893, Archiv. fiir Phvsiol. 



PfKiger, Bd. 54, p. 165 (reactions to chemical stimuli). Ibid., 1894, Bd. 57, p. 495. — Davidoff and Garijev, 1907, 



Bericht Zool. Station, Villa Franca, 47, p. 12. 

 Geryonia mexicana + Carmaris rosea (young medusa 1 ), Agassiz, A., and Mayer, 1902, Mem. Museum Comp. Zool. at Harvard 



College, vol. 26, p. 149, plate 4, figs. 17, 18. 

 Geryonia (Carmarina) hastata, StschelkanowzefF, 1906, Mitth. Zool. Sta. Neapel, Bd. 17, p. 479 (two sorts of Cunina larva? 



infest Geryonia). 



Adult medusa. — The bell is nearly hemispherical, with moderately thick walls, and is 35 

 to 80 mm. in diameter. There are 6 long, hollow, contractile, radial, and 6 short, solid, inter- 

 radial tentacles. The long tentacles are in the radii of the 6 radial-canals and are highly con- 

 tractile and provided with rings of nematocysts. The short, interradial tentacles project from 

 the sides of the bell at a short distance above the margin and are studded along their aboral 

 sides with wart-like clusters of nematocysts. These interradial tentacles are very stiff and 

 brittle and are often lost, leaving only the 6 long, radial tentacles. There are 12 inclosed lith- 

 ocysts above the velum near the bases of the 12 tentacles. Each lithocyst contains a single 

 spherical concretion. There are well-developed circular muscles in the subumbrella. 



There are 6 radial-canals and typically 6x7 straight, blindly ending centripetal vessels 

 which arise from the wide circular vessel. In each interradial sextant the interradial centrip- 

 etal vessel is longest, the 2 adradial ones being not quite so long, and the 4 intermediate ones 

 being much shorter. 



The solid, gelatinous peduncle is conical to trumpet-shaped, about as long as the bell- 

 diameter and as wide at its base as is the bell-radius. It tapers to a narrow end outwardly. 

 Well-developed, longitudinal muscles extend down the interradial sides of the peduncle and 

 enable it to bend from side to side, or to contract to a considerable degree. These muscles of 

 the peduncle extend also along both sides of each of the 6 radial-canals from the region of the 

 gonads to the base of the peduncle. On the peduncle itself they form 6 broad bands, extending 

 down each interradius between the sides of the radial-canals. The same arrangement of muscle 

 fibers is seen in Liriope, excepting that in Geryonia there are 6 and in Liriope only 4 interradial 

 muscle-bands. 



The stomach is short with 6 simple lips and a more or less well-developed tongue- 

 shaped projection is usually to be seen in the throat; but this is very variable in its development. 

 The 6 gonads are elongate and more or less heart-shaped and extend over the subumbrella 

 from near the base of the peduncle to points about midway between base ot peduncle and 

 ring-canal. When mature the sides of adjacent gonads nearly touch one the other, 



