720 MEDUSAE OF THE WORLD. 



HYDROMEDUS^E. 



Maas, 1909 (Abhandl. Math. phys. Klasse der K. Ba)-er. Akad. der Wissenschaft, Miin- 

 chen, Suppl. Bd. I, Abhandl. 8), gives a description of 23 hydromedusae from Japan obtained 

 upon Doflein's voyage. 



The old species are Cytais vulgaris, Tiara papua, Proboscidactyla flavicirrata var. stolon i- 

 fera, Spirocodon saltatnx, Ettcheilota paradoxica, Phialidium pacificism, Phialidium discoida, 

 Mesonema pensile, Gomonemus vertens var. depressum, Ohndioides formosa, Liriope rosacea, 

 Rhopalonema velatum, Aglaura hemistoma, jfLgina rosea, Solmundella bitentaculata, Cunina 

 peregrina, and Salmans rhodoloma. 



The new forms are called Sarsia japonica, Nemopsis dofleini, Turritopsis nutricula var. 

 pacifica, and Willsia pac:fica. A Zanclea and an Obelia are possibly new. 



It is interesting that Eucheilota paradoxica, known hitherto only from the Florida-Bahama 

 region, should be reported from Japan. 



One of the most valuable features of Maas's paper is his redescription, accompanied by an 

 excellent account of the post-embryonic development of Spirocodon saltatri\. Reviews of his 

 account of this, and of the new forms, are presented in this Appendix. 



An important paper upon Arctic Hydromedusae and Scyphomedusae is that of Hartlaub, 

 1909, Croisiere Oceanographique Belgic a dans la Mer du Gronland, Meduses, 18 pp., planches 

 76-77. Unfortunately this has reached me too late to be reviewed for this work. 



Pennaria tiarella (see page 25, Vol. I). 

 Pennaria tiarella, HARGITT, G. T., 1909, Bull. Mus. Comp. Zool. at Harvard College, vol. 53, p. 164, 5 plates, 44 figs. 



Hargitt studies the development of Pennaria tiarella and finds that the obcyte nucleus 

 dissolves within the germinative vesicle before the nuclear membrane is ruptured. The linine 

 network of the germinative vesicle extends to the nucleolus, so that an interchange of substances 

 may possibly occur between the chromatin and the nucleolus. 



The two polar bodies appear to be formed at about the time of the liberation of the medusa, 

 by a process of mitosis of which Hargitt gives a detailed account. 



Fertilization usually occurs after the polar bodies have been formed. The cytoplasm is 

 very active at this time, forming protuberances upon the surface of the egg. The male and 

 female pronuclei unite by apposition. 



The first cleavage spindle seems to form from the cytoplasm. The cytoplasmic division 

 is delayed, the second nuclear division being completed before the first cleavage furrow has 

 cut half through the egg. 



Hargitt disagrees with Beckwith, 1909, and finds that the polar bodies are seen only at or 

 near the time of the liberation of the medusae, about 7 p. m. He also finds, contrary to Beck- 

 with, that the nucleolus disappears within the germinative vesicle before the dissolution of the 

 nuclear membrane, whereas Beckwith states that it is cast out into the cytoplasm. 



Corymorpha nutans (see page 31, Vol. I). 

 Cor\morpha nutans, MALARD, 1907, Bull. Museum Paris, p. 563. TORREY, 1907, Science, vol. 25, p. 734. 



Malard finds Corymorpha nutans when dredging in deep water northeast of the He Tati- 

 hou, coast of France, and Torrey observes spontaneous fission in the stems of the hydroid. 



Sarsia rosaria (see page 59, Vol. I). 

 Sarsia rosaria, KISHINOUYE, 1910, Journ. College of Sci., Tokyo, vol. 27, art. <j, p. 24. 



Kishmouye finds this medusa off the Kurile Islands, north of Japan. A. Agassiz records 

 it from the Pacific coast of North America. 



Sarsia japonica Maas. 

 Sarsia japonica, MAAS, 1909, Abhandl. Akad. Wissen., Munchen, Suppl. Bd. I, Abhandl. 8, p. 6, taf. i, fig. i. 



Bell 12 to 15 mm. high, 4 to 6 mm. wide, with flatly rounded apex. Bell walls 2 mm. 

 thick. Manubnum nearly cylindrical, four-filths to five-sixths as long as the depth of the bell- 

 cavity. Gonads scattered irregularly over the manubnum from the base to near the mouth. 



