RHIZOSTOM.-E — LOBONEMA, THYSANOSTOMA. 



691 



The mucous membranes give rise to a thin copious secretion. The patient becomes hysterical, 

 coughs almost incessantly and throws himself about the bed, nauseated, weeping, and with an 

 anxious congested face. The pulse becomes rapid and some degree of fever usuall)- develops. 

 The general symptoms develop in from lo to 15 minutes after the infliction of the sting. 



The most efficient remedy was found to be a hypodermic injection of one-sixth to one- 

 eighth grain of morphine sulphate and an external application of an alkaHne solution such 

 as bicarbonate of soda. A report upon these cases is presented by Dr. Old in the Philippine 

 Journal of Science, vol. 3, p. 329, 1908. 



RHIZOSTOMATA LORIFERA Vanhbffen. 



Rhizoslomatn lorijera, Vanhoffen, 1888, Bibliotheca Zoologica, Bd. i, Heft. 3, p. 45. — Maas, 1903, Scyphonu-dust-n dcr Sibo^a 



Exped., Monog. 11, p. 75. 

 LeptohrachidiX, Claus, 1883, Organisation und Entwick. Mcdusen, Leipzig. — von Lfndenfeld, 1888, Zeit. fiir wissen. Zool., Bd. 



47, p. 211. — Maas, 1906, Revue Suisse de Zool., tome 14, p. 104. 



CHARACTERS OF THE GROUP. 



Rhizostom.'e with very elongate, narrow, lash-like mouth-arms. The lower parts of the 

 arms are 3-winged in cross-section, the mouths being developed upon and near the angles. 



The upper parts of the mouth-arms are very short and partially 

 fused to the arm-disk by a series of arches spanning from one 

 arm to another. The ring-muscles of the subumbrella are pow- 

 erfulh' and the radial muscles weakly developed. 



The Rhizostoinatii lorijera are only a subordinate group of 

 the Rhizosiomata triptera from which they have been derived by 

 the elongation of the mouth-arms and the reduction of the lateral 

 expansions of the arms. A description of the genera follows: 



Thysanostoma L. Agassiz, 1862. Mouth-arms without terminal clubs. 3 rows 

 of frilled mouths extend down the angles throughout the entire length of 

 the lower arm. 



Lorijera Haeckel, 1880. Similar to Thysanostoma but with a naked knob 

 at the lower end of each arm. 



Leptobrachia Brandt, \%'i^% = Leptobrachia+ Leonura'HAt.cK.^i.. Mouths confrne:! 

 to the lower and upper ends of the mouth-arms, so that the mouth-anns are 

 devoid of mouths in the mid-regions of their lengths. 



Genus THYSANOSTOMA L. Agassiz, 1862. 



Thysanostoma, Agassiz, L., 1862, Cont. Nat. Hist. U.S., vol. 4, p. 153. — Haeckel, 1880, 



Syst.der Medusen,p.625. — Vanhoffen, 1888, Bibliotheca Zoologica, Bd. I, Heft. 



Fig. 419. — Diagrammatic representa- 3, p. 45.— Kishinouye, 1895, Zool. Magazine, Tokyo, vol. 7, p. 133.— Schultze, 



tion of the form and position 1898, Denkschr. Med. Nat. Gesell., Jena, Bd. 8, p. 448.— Maas, 1903, Scypho- 



of the mouth-arms in the Rhi- medusen der Siboga Eiped., Monog. 11, pp. 75, 81; 1906, Revue Suisse de Zool., 



zostomata lorijera. tome 14, p. 105. 



The type species is Thysanostoma thysantira from the Indo-Pacific region. It is possible 

 that Lesson's inadequately described Rhtzostoma brachyura may be the same medusa. 



GENERIC CHARACTERS. 



Rhizosiomata lorijera having mouth-arms bearing 3 rows of frilled mouths from base to 

 lower end, without a terminal club. 



Among characters of minor importance, the 4 interradial, subgenital ostia are wider than 

 the perradial columns between them. There are 8 rhopalar canals, and a ring-canal which 

 gives off a network of vessels on both its inner and outer sides. This network connects with 

 all the radial-canals and also at numerous points with the central stomach. The well-devel- 

 oped circular muscles are only partially interrupted in the 8 principal radn. There is a small, 

 shallow, exumbrella pit above each sense-organ, without furrows in the floor oi the pit. 



