58 DISCOVERY REPORTS 



examined several specimens, the young gonads first appear as eight small evaginations on the radial 

 canals close to the stomach; later they are more or less completely divided into two lateral sacs. 

 Their further development may proceed more or less irregularly, and the limits betw^een the gonads 

 and the eight radial diverticula of the upper portion of the stomach may be indistinct. In the largest 

 specimen, 6-5 mm. wide, examined by Vanhoffen (1912 a) the gonads are divided into two parts, 

 'von denen die obere der Wurzel der Radialkaniile anUegt, wahrend die untere Partie mit zwei 

 Aussackungen auf dem oberen achtfach gefallteten Teil des Magens ruht'. The accompanying text- 

 figures show that the gonads of Vanhoffen's specimen were at an immature stage. According to 

 Ranson (1936), who examined two specimens from the Mediterranean 7-8 mm. in diameter, the 

 structure and position of the gonads are difficult to state precisely. In his specimens the gonads, 

 issuing from the radial canals close to the stomach, have attained a considerable size; they may touch 

 each other interradially and even fuse together. 



In one of the present specimens (St. WS 160, 6 mm. in diameter) the manubrium is short and broad. 

 Gonads (PI. V, fig. 4) containing numerous large eggs are developed as eleven radial lobes from the 

 upper surface of the stomach, very unequal in size and irregularly distributed, and, moreover, small 

 additional sac-shaped gonads issue from the radial canals at a short distance from the stomach, 

 usually in pairs. No additional gonads are developed on the radial canal above the largest of the 

 gonadial lobes issuing from the stomach. 



In the other specimen from the same locality, also 6 mm. wide, the structure is very similar, but 

 the gonads are less developed. The specimen from St. WS 388 is young, 4 mm. wide; the stomach 

 is short, its basal part has 16 radial folds, from which the gonads issue as irregular radial lobes; there 

 are no additional gonads on the radial canals. 



The paired, sac-shaped gonads on the proximal part of the radial canals in the specimens from 

 St. WS 160 correspond to those described and figured by Maas in A. amplum;t\\e gonadial lobes issuing 

 from the basal wall of the stomach resemble the gonads of A. tetragoniiim (Vanhoffen 19 12 a, p. 377. 

 Text-figs. 12-15). This medusa, which was up to 12-5 mm. wide, had four gonads, kidney-shaped, 

 in the walls of the stomach adjacent to the subumbrella; in other respects the species was similar to 

 A. ampltim. Considering the irregularities observed in A. amphim, it seems very probable to me that 

 A. tetragoniiim is only an aberrant form of A. amphim; it was found in the Atlantic Ocean near the 

 equator within the area of distribution of A. amphim. 



Since gonads may be developed in the stomach wall as well as on the radial canals in A. amphim, 

 this species forms a connecting link between A. antarcticum, in which the gonads are restricted to 

 the stomach walls, and A. australe in which the gonads are situated on the proximal parts of the 

 radial canals. These three species may therefore be regarded as belonging to one genus, Arctapodema, 

 in spite of the considerable difference between the two extremes. 



Distribution. A. amphim occurs in the intermediate and deep layers of the Atlantic and Indian 

 sectors of the Antarctic Ocean; in the tropical Atlantic; and in the Mediterranean. 



Arctapodema australe (Vanhoffen 19 12) 

 (PI. V, figs. 5, 6, text-fig. 9) 



iQiZrt Isoncma australe Vanhoffen, p. 376. Text-figs. lo-ii. 

 1936 Arctapodema australe Ranson, p. 157. 



Occurrence: St. 1753. 27. iv. 36. 32° 00' 24" S, 68° 50' 54" E. Between South Africa and Australia. Net: 

 TYFB 2900-1400 m. I specimen (for distribution, see chart, text-fig. 9, p. 57). 



This species was well described and figured by Vanhoffen. His only specimen was 23 mm. wide and 

 14 mm. high, with about 112 tentacles. The present specimen is only 7-5 mm. wide and 5 mm. high, 



