94 FOSSIL MEDUSA. 



Medusina bicincta Haeckel. 

 PI. XLV, fig. 2. 



Medusites bieinetus Haeckel, 18G9. Zeitschr. fiir wiss. Zoologie, Vol. XIX, pp. 554-555, 



561, PI. XLII, fig. 3. 

 Medusites bieinetus Haeckel, 18S0. System der Meduseu, p. 648. 

 Medusites bieinetus Amnion, 1880. Abhandl. Math.-phys. Glasse Konigl. bayerischeu 



Akad. Wiss., Vol. XV, p. 158. 



The impression of this medusa is very weak and only with difficulty can the out- 

 lines be distinguished of a central cruciform figure surrounded by two circular zones. 

 At first sight this form appears to be an example of Medusites (Trachyne mites) deper- 

 ditus, but by a more careful inspection essential differences become apparent. In the 

 first place, the external circular zone is not simple, but double, and, secondly, the 

 eight radial lines of the mid-field lie at alternately unequal intervals. 



The interpretation of this very obscure configuration is difficult and uncertain. 

 The external of the two peripheral rings (u) is probably to be referred to the thickness 

 of the gelatinous disk ; the inner (c) either to a very broad ring canal or to a strong 

 velum. The four narrower of the eight three-cornered facets of the mid-field (r) are 

 probably to be interpreted as four radial canals, widening toward the periphery, the 

 four broader ones as interradial areas. 1 



Medusina staurophora Haeckel. 

 PI. XLII, fig. 3. 



Medusites staurophorus Haeckel, 1869. Zeitschr. fiir wiss. Zoologie, Vol. XIX, pp. 



555-556, 561, PL XLII, fig. 6. 

 Medusites staurophorus Haeckel, 1880. System der Meduseu, p. 648. 

 Medusites staurophorus Amnion, 1886. Abhandl. Math.-phys. Classe Konigl. baye- 



rischen Akad. Wiss., Vol. XV, p. 158. 



The outline of the disk of this medusa is so faint as to be scarcely discernible. 

 It appears to form a circle with a diameter of 50 mm ; 6 mm from this runs another con- 

 centric circle, just as indistinct. This peripheral zone is probably to be referred to the 

 thickness of the umbrella mass. There is no trace of a ring canal. On the other 

 hand, there is in the middle of the disk a sharply defined cross, composed of two thick 

 mounds intersecting at right angles. In the middle of each mound runs a radial furrow 

 or channel, which gradually enlarges on approaching the center. In the midfield the 

 furrows of the four radial mounds, or cross-quadrants, unite to form a small, flat, 

 funnel-shaped excavation. This is in any case to be referred to the gastral cavity, and 

 the four crossing furrows to the four radial canals passing outward from the stomach. 

 The thickness of the prominent ridges leads to the conclusion that the walls of the 

 radial canals (especially toward the center of the disk) were solid and thick, perhaps 

 supported by cartilage, as in many trachynemids. A conclusion as to the systematic 

 position of this medusa can not be formed, on account of the very deficient impression. 2 



1 Zeitschr. fiir wiss. Zoologie, Vol. XIX, 1869, pp. 554-555. : Loc. cit.,pp. 555-556. 



