MEDUSA. I. 



species are given in my paper on the Anthomedusae and Leptomedusae of the "Michael Sars"). Now 

 it is not difficult to fancy a transition from the facts as established in these species to the type of 

 gastrogenital organs found in most Laodiceidce. If the gonads disappear in the interradial parts, we 

 have, on each side of the radial canals so far as these are connected with the edges of the stomach, 

 a series of gonadial folds, forming together a continuous, folded band along the part of the canal 

 concerned. An outward displacing (towards the bell-margin) of these gonads will have the effect, that the 

 proximal ends are somewhat withdrawn from the centre of the umbrella, while the distal ends, being 

 removed outwards, will drag along with them the adjacent parts of the wall of the stomach, forming a 

 funnel-shaped extension of the stomach along the lower side of each of the radial canals. Then we have 

 the type, which is found in Ptychogena and Laodicea (see below). The modification of this type within 

 the different forms, here dealt with, will be mentioned below under the descriptions of the species. 



The emancipation of the gonads from the stomach is not so far advanced in the Laodiceida 

 (the species here described) as in the other Leptomedusae; this indicates a lower systematical position 

 nearer to the Anthomedusae. In Laodicea, Ptychogena and Staurophora the gonads are developed in 

 folds of the lateral walls of the radial canals; in the case of the two first mentioned genera the 

 proximal parts of the gonads are frequently developed in the walls of the stomach along both sides 

 of the lines (the cross-shaped figure) by which the stomach is attached to the subumbrella. In Stauro- 

 pliora the structure of the gastrogenital organs is secondarily complicated (see below). In Chro- 

 matonema the gonads do not form continuous bands, but consist of a row of sack-shaped invaginations 

 on each side of the radial canals; some of the proximal gonadial sacks are situated within the corners 

 of the stomach in the dorsal walls of the latter along the arms of the cross-shaped figure. These gonadial 

 sacks, with their narrow, split-shaped openings, recall the gonadial sacks, arranged in rows, in Calycopsis. 



Genus Chromatonema Fewkes. 

 Chromatonema rubrum Fewkes. 



Plate I, figs. i8. 

 Chromatonema rubrum Fewkes 1882. Acalephae, East Coast of New England. Bull. Mus. Comp. Zool. 



Vol. 9. No. 8, p. 305. PI. I, fig. 41. 

 Thaumantias Mayer 1910. Medusae of the World. Vol. I, p. 199. 



Kramp 1913. Medusae, "Tjalfe"-Exp. Vidensk. Meddel. Dansk uaturh. Foren. 



Bd. 65, p. 267. 



Kramp 1914. Meduser og Siphonophorer. - - Conspectus Faunae Groenlandicae, 



p. 419. 



? Ptychogena erythrogonon Bigelow 1909. Medusae, Eastern Tropical Pacific. -- Mem. Mus. Comp. Zool. 



Vol. 37, p. 150. PI. 5, fig. i. PI. 38, figs. 8, 9. PI. 39, figs. 17. 

 ? Hertiuigi Vanhoffen 1911. Deutsche Tiefsee-Exped. Bd. 19, p. 220. Taf. 22, Fig. 9. Textfig. 13. 



Description. - The bell is somewhat higher than a hemisphere, the gelatinous substance 

 very thick, evenly rounded at the top, gradually tapering towards the bell margin. The base of the 

 manubrinm is broad, quadrangular, attached to the subumbrella along the arms of a perradial cross, 



