b 



BIGELOW: MEDUSAE FROM THE MALOIVE ISLANDS. 263 



Nausithoe punctata Kolliker. 



Ivllliker, 1853, Zeit. fiir Wiss. Zoologio, \n\. IV. 



Nausitlioe punctata, var. racifica, Agassiz & Mayer, 1902, Mem. Mus. Comp. Zom!., 



vol. 26. 



Plate 6, Fig. 21. 



In the descriptions and figtires of this genus, given by Kolliker, Agassiz and 

 Mayer, Mayer, Haeckel, and Gegenbauer, there has been a great deal of con- 

 fusion as to the relative radial positions of the marginal tentacles, gonads, and 

 groups of gastric cirri. Kolliker, who established the genus, figures Nausithoe 

 punctata with the gastric cirri and gonads in the tentacular radii (Zeit. fiir 

 Wiss. Zool., bd. 4, p. 323). Gegenbauer, who has given the best figures of 

 this species, followed his example (Arch. Anat. and Phys., 1853, p. 239). 

 Haeckel (System, part 2, 1879) says that the gastric cirri are in the radii of 

 the sense organs (gonads and tentacles adradial) ; Avhile Mayer says of Nausi- 

 thoe punctata that the gastric cirri lie in the radii of the marginal sense organs, 

 but in his figures they are in the tentacular radii! (Bull. Mns. Comp. Zool., 

 vol. 37, no. 2.) Finally, Agassiz and Mayer (Mem. M. C. Z., vol. 26, no. 3, 

 1902) figure Nausithoe punctata var. pacifica and Nausithoe picta with them 

 in the tentacular radii. 



In our specimens the arrangement was as follows. The four angles of the 

 moitth, and the four groups of gastric cirri which alternate with them, are in 

 the radii of the eight marginal sense organs. The eight gonads lie in the radii 

 of the eight tentacles. There are thus si.xteen distinct radii, eight tentacular, 

 in which lie the eight gonads, and eight ocellar, corresponding to the finir 

 groups of gastric cirri, and the four arms of the cruciform mouth. This agrees 

 with Haeckel's statement and Mayer's description. 



The bell is flat, of the Ephyra-like outline typical of the genus, seven to nine 

 mm. in diameter. There are eight stiff, solid tentacles arising from the clefts 

 between the eight marginal lobes. Each marginal lobe is subdivided into two 

 lappets, and between each two lappets there is a sense organ. Each sense organ 

 contains a spherical otocyst and a proximal dark-brown ocellus, provided with 

 two nerve fibres and a lens. The mouth is cruciform, and alternating with the 

 arms of the cross there are four groups of gastric cirri, from two to five in each 

 group. The eight gonads are pale reddish-brown. There is a ring of circular 

 muscle fibres, occupying most of the subumbrella between the bases of the ten- 

 tacles and the periphery of the stomach, and a strand of radial fibres inins from 

 near the stomach out into each of the sixteen marginal lappets. 



Seven specimens of different ages. December 26, Male atoll, near Male 

 island, surface. January 2, Suvadiva atoll, near Dandu island, surface. 



This form is very close to Nausithoe punctata, from which it differs only in 

 the brighter color of the gonads, and the rarity of yellow pigment spots on the 

 exumbrella, features of which the .systematic importance is too slight to war- 

 rant the establishment of a new variety. 



