10 



HJALMAR BROCH. 



[REP. OF THE "MICHAEL SARS" NORTH 



ously known species of Naasithoe as far as I am aware. 

 Another character of the margin distinguishes this species 

 sharply from A r . rubra, viz. eight small lappets, inserted 

 between the larger marginal ones, each carrying a rho- 

 palium at its distal end. The outlines of the larger lap- 

 pets could not be traced with certainty, the margins of 

 the specimens examined being more or less damaged. 

 The rhopalium itself (pi., figs. 3 and 4) presents the 

 same features as in Nausithoe limpida Hartlaub. 1 ) On 

 the exumbrellar side a carina runs along the rhopalium; 

 the keel disappears a little higher up the small lappets. 

 The rhopalium consists of litocyst, covering scale, and 

 ventral bulbus; the ocellus found in Naasithoe limpida, 

 is absent in N. atlantica. In this negative character it 

 corresponds to N. rubra, and we see in it an adaptation 

 to life in deep water, as already pointed out by Bigelow. 



This species was found in the eastern parts of the 

 Atlantic (compare the map, fig. 5) between the submarine 

 ridge extending northwards from the Azores and the Euro- 

 pean slope. One of the stations (56) is situated just south 

 of the Azores. 



Nausithoe globifera n. sp. 

 PI., figs. 5-8. 



Seven specimens of an interesting medusa were taken 

 at five stations in the eastern part of the Atlantic. At first 

 sight they seemed to fall systematically between Atolla 

 and Periphylla, but closer examination showed that they 

 must be referred to Nausithoe. The margin is provided 

 with sixteen lappets with unbranched lappet-channels, and 

 between these eight rhopalia alternating with eight ten- 

 tacles. The rather arched and solid central disc is like 



Station 



Lat. N. 



Long W. 



Depth in 

 metres 



Number of 

 specimens 



Measurements in rem, 

 D r= total diameter 

 C = diameter of the central disc. 



56 

 90 

 92 



36° 53' 

 46° 58' 

 48° 29' 



29° 47' 

 19° 6' 

 13° 55' 



500 

 500 

 500 



2 

 5 

 1 



f D = 18 ) 



I P .„ > one specimen very much damaged 



| D = 24, 25, 26, 28 \ the fifth specimen very much 

 \ C = 13-5,13, 14, 15 ) damaged 

 / D = 26 

 t C = 12 



It is rather difficult to trace the ringmuscle on the 

 sub-umbrellar side. The gonads, as mentioned above, 

 occupy the position described by Haeckel for Nausicaa, 

 and later observed by Maas in Nausithoe picta. In adult 

 specimens (pi., fig 2.), we observe a distinct space between 

 the gonads at the four corners of the stomach, but between 

 the radii the limits may be traced or the may wholly fade 

 away, so that apparently an interradial coalescence takes 

 place. In opposition to what takes place in Palephyra, 

 in which Vanhoffen speaks of a perradial distal approxi- 

 mation of the bean-shaped gonads, we find here an 

 approximation of the proximal parts of the gonads in the 

 interradius. The species might thus be referred to Nau- 

 sicaa, but Maas has proved that Nausicaa cannot be kept 

 separate from Nausithoe'. 



The stomach is rather short, having a rounded quadran- 

 gular base. At the corners the walls are a little longer 

 than elsewhere, apparently an indication of "mouth-arms". 

 The gastric cirri are simple and small, and in single rows. 

 We find in all about 80 cirri. 



N. atlantica is doubtless a deep-sea medusa, as shown 

 by the table above giving details of the specimens taken 

 by the youngfish trawl. 



the greater part of a globe resting on the marginal parts, 

 and led me to confer the name of globifera upon the 

 species. 



The medusa attains a diameter of at least 17 mm. 

 The exumbrellar surface of the bell is dotted all over 

 with small groups of nematocysts; no general form could 

 be traced in the nettle-spots, which are colourless. The 

 medusa at once attracts attention on account of its glo- 

 bular appearance and its vivid colours. The stomach is 

 brownish or quite black, rarely somewhat yellowish brown, 

 the conspicuous gonads are light brownish or yellowish, 

 occasionally of a rather reddish colour, and project 

 sharply from the dark background. The opaque ring- 

 muscle, the tentacles, and the rhopalia are also of a light 

 brownish hue. 



The high arched central disc (pi., fig. 5 and textfig. 

 6) contains a solid jelly-like substance, and is covered all 

 over with nettle-spots. The furrow is strongly marked. 

 The pedalia of the marginal parts are not prominent, and 

 in many cases it is rather difficult to trace them. The 

 sixteen lappets (pi., fig. 6) are broad and rounded with 

 equal interspaces. Between them eight rather stout solid 

 tentacles alternate with the eight rhopalia. 



1 ) Meduses (Due D'Orleans: Croisiere oceanographique accomplie a bord dc la Belgica dans la Mer dii Gronland 1905). Bruxclles 1909, p. 14. 



