286 



MEDUSA OF THE WORLD. 



dant, yet he found only a single individual with the medusa-bud. It is possible that this so- 

 called medusa-bud may have been a parasitic Halcampa ( ?). 



Genus MITROCOMA Haeckel, 1864. 



Milrocoma, Haeckel, 1864, Jena. Zeitschrift fur Naturwiss., Bd. 1, p. 332.— Hertwig, O. und R., 1878, Nervensyst. und Sin- 

 nesorgane der Medusen, p. 81, taf. 6, fign. 10, II, 14. — Metschnikoff, 1886, Embryol. Studien an Medusen, Wien, pp. 

 23, 37, 54, 75, 82, taf. 3, fign. 20-33; ta f- 4> fign-'i >6 (development showing that Cuspidella is the hydroid). — Hartlaub, 

 1905, Zoolog. Jahrbiichern, Suppl. 6, p. 589. 



Halopsis (cruciata), Agassiz, A., 1865, North Amer. Acal., p. 102. 



Tiarops, Romanes, 1876, Journ. Linnean Soc. London, vol. 12, p. 526. 



Phialis + Mitrocomium + Mitrocomella + Mttrocoma, Haeckel, 1879, Syst. der Medusen, pp. 181, 184, 188. 



Halopsis, Maas, 1893, Ergeb. der Plankton Expedition, Bd. 2, K. c, p. 57, taf. 6, fign. 3-6. 



Mitrocomclla, Browne, 1903, Bergens Museums Aarbog, No. 4, p. 17. 



Cuspidella (hydroid), Hincks, 1868, Hist. British Hydroid Zooph., p. 209. 



This genus was founded by Haeckel, 1864, for Mttrocoma atnur, of the Mediterranean 

 (and Atlantic ?). 



Fig. 1 52.— Milrocoma annx. From life, by the author. Zoological Station, Naples, January, 1908. 



A. Oral view of open mouth. B and C. Parts of bell-margin showing cirri and otocysts. D. Female gonad. 



GENERIC CHARACTERS. 



Eucopidae with 8 or more lithocysts which consist of open folds, or pockets, of the velum, 

 and contain numerous (3 or more) concretions. There are numerous cirri. The 4 gonads 

 are developed upon the 4 radial-canals. There is no well-developed peduncle and there are 

 4 prominent lips. The hydroid is Cuspidella Hincks, 1866. 



We include within this genus a number of Eucopidae which have from 8 to 80 or more large, 

 open lithocysts, each of which usually contains a large number of concretions. The tentacles 

 vary in number in the different species from 8 to 200, or more. It seems inexpedient to draw 

 any generic distinctions between these various species based upon the number of lithocysts or of 



