692 



MEDUS.E OF THF. WORLD. 



The onlv difference between this genus and the closely allied Lorijera is that the iVilled 

 mouihs are developed even to the tips of the lower ends of the mouth-arm and there is no 

 terminal club, whereas Lorifera has a naked terminal club. 



Thysanostoma thysanura Haeckel. 



( ?) RAiia.'ioma brachyura, Lf.ssos, R. P., 1829, Voyage dc la Coquillt, Zoophyt., tome z, p. 153; 1830, Centurir Zoologiquc, 

 p. 217, planchc 80. 



Tli<,ianosiomii ihysanura, HArricrL, 1880, Syst. dcr Mejuscn, p. 625, taf. 39, fign. 1-9. — Schultzf, L. S., 1898, Denkschr. 

 Med. Nat.Gesell., Jrna., Bd. 8, p. 448, laf. 33, fig. 3; taf. 34, fig. 8.— Maas, 1903, Scyphomcduscn dcr Sihoga Expojition, 

 Monog. II, p. 75. l^f- 'O, fign- 93, 94; 1906, Revue Suisse de Zool., tome 14, p. 105.— Kishinoitve, 1910, Journal Col- 

 lege of Sci., University of Tokyo, vol. 27, art. 9, p. 23. 



Thysanosioma denicriipum, KiSHiNOuvr, 1895, Zoological Magazine, Tokyo, vol. 7, No. 83, p. 133, plate 18, figs. 1-13. 



The bell is 90 to 120 mm. wide. The exumbrella exhibits polygonal facets or granular 

 elevations which arc larger at the center ihan at the margin. Its outline is dome-like and 

 Hat;er than a hemisphere, recalling the appearance of a shield. There are 8 marginal sense- 



Fic. 420. — Thysanostoma thysanura. Drawn by the author, from a specimen taken in a 

 seine by the U. S. Fisheries Bureau steamer Albatross at Panabutan Bay, Philip- 

 pine Islands, Feb. 6, 1908. 



A, oral view showing all but one of the mouth-arms cut off. One mouth-arm is cut off 

 close to its point of origin, but the other fi are cut off at their widest, V-shaped 

 regions. B, side view of basal part of mouth-arm, with section of same. C, sec- 

 tion near distal end of mouth-arm, somewhat enlarged, showing T-shapc of cross- 

 section of arm the and 4 arm-canals. D and E. rhopalar lappets from subum- 

 brella and eiumbrella sides respectively. 



organs which are flanked b)' i6 small, pointed lappets and between each successive pair of 

 sense-organs are 6 to 12 bluntly rhomboidal lappets which are very variable in size even in 

 different parts of the same octant. The sense-clubs have a pigmented mass of lithocysts 

 and there is a very small, shallow, simple, exumbrella pit. 



The 8 mouih-arms are each about 1.5 to 3 times as long as the bell-diameter; upper arm 

 only about one-twelfih as long as the lower arm. Lower arm delicately formed, 3-winged 

 and Y-shaped or T-shaped in cross-section throughout its length; in its upper pan it tapers 



