MUGGIAEA ATLANTICA. 187 



Muggiaea atlantica Cunningham. 



Muggiaea pyramidalis Haeckel, '88b, p. 137 (non Busch '51). 



Cucubalus pyramidalis Haeckel, '88b, p. 109. Eudoxid. 



Muggiaea allanlica Cunningham, '92, p. 214; Gough, :0.5, p. 1; Vanhoffen, :06, p. 13. 



(Non Eudoxia eschschoUzi Johannsen and Levinsen, :03). 



Plate 7, Fig. 1; Plate 9, Figs. 7, 8. 



Station 4571 surface 1 specimen 8 mm. long. 



" 4598 300 fathoms to surface 1 " 7 " " 



" 4611 " " " " 68sppfimcns 3-5 " " 



" 4655 " " " " 25 " 6-7 " " 



" 4673 " " " " 2 " 6,7 " " 



The specimen,s agree even to minor details with Cunningham's account 

 and figure. 



Although at least the basal part of the stem was well preserved in most 

 cases, in none could I find any bud which might be identified as a reserve bud 

 for a future posterior nectophore. 



The diagnostic features of M. atlantica are as follows : — There are five 

 ridges at the apex, and these run to the base without branching; there are no 

 basal teeth, and the only suggestion of such structures is a slight prominence of 

 the angles at the basal terminations of the ridges (Plate 7, fig. 1). The degree 

 of serration of the ridges is variable, some specimens showing it strongly from 

 apex to base, others, hardly at all; and there are various intermediates between 

 these two extremes. The hydroecium, which varies very little, reaches to 

 slightly less than one third the length of the nectosac, as Cunningham shows it; 

 but it extends basally some distance below the bell opening, so that its entire 

 length is nearly one half that of the nectosac. In no example does it reach the 

 mid-level of the nectosac, as Haeckel describes it; but his account is altogether 

 insufficient. Apically the hydroecium is conical. The dorsal hydroecial wall, 

 below the level of the bell opening, is divided longitudinally, forming two sym- 

 metrical lateral wings (Plate 9, fig. 8), a character not mentioned by Cunning- 

 ham. The lateral basal margins of the hydroecium are nearly straight. (Plate 

 9, fig. 7.) 



Somatocyst. This structure is nearly cylindrical, very slender, and as a rule 

 terminally dilated with a large oil bubble. It is closely apposed to the ventral 

 wall of the nectosac. In the smaller specimens (3-4 mm.) it considerably 

 surpasses the apex of the nectosac (Plate 7, fig. 1); but with increasing growth 

 it becomes proportionately shorter and shorter. In specimens 6 mm. long. 



