BIGELOW: THE CTENOPHORES. 389 



beginning. Furthermore, each type of rib characterizes several 

 species; and no form is yet known intermediate between the two 

 For these reasons Pandora seems worthy of generic rank. The genus 

 is especially interesting because it may afford a case of " dissogonie" in 

 the cases of P. pandorina Moser and of P. flemmingi Eschscholtz. 

 Moser (:03, p. 26) has given a thorough discussion of these two 

 species, pointing out the possibility that they may belong to a single 

 developmental series. Briefly stated, the difference between the two 

 is that pandorina is small, with very large stiff cilia about the mouth, 

 and sexually mature, while flemmingi is much larger (up to 25 mm. 

 high) with small, slender lip-cilia, and not mature even at this large 

 size. Xo intermediates have yet been found, and it is to be hoped 

 that some student will shortly have access to more complete series 

 of the two. 



P. mitrata Moser (:08a) from Japan differs from P. flemmingi in 

 being cylindrical when adult, and in the fact that the branches of 

 the meridional canals run toward the mouth and anastomose much less 

 often than they do in flemmingi. According to Moser its gastric cilia 

 are unusually thick and long, as in P. pandorina. The "Albatross" 

 collection contains a single specimen which agrees very closely with 

 Moser's figure and descriptions of mitrata. 



The Beroe punctata of Chamisso and Eysenhardt is also included 

 in Pandora, by Moser ( : 08a) on the strength of Eschscholtz's state- 

 ment that its ribs were of unequal lengths. Xo unquestioned record 

 of it has since been obtained. Until it is redescribed it must remain on 

 the doubtful list. 



Pandora mitrata Moser. 



Pandora mitrata Moser : 07, p. 451, :08a, p. 34, taf. 1, fig. 1-3; 

 :09, p. 159. 



Station 4727, surface, one specimen, 16 mm. high, in good condition. 



The single example agrees so well with Moser's figures that a 

 detailed account is unnecessary. The ribs are slightly longer, the 

 subventral extending over about two thirds, the subtentacular over 

 slightly less than one half of the body; but the mouth-region is some- 

 what contracted, so it is positive that the discrepancy is to be ex- 

 plained at least partially by preservation. The branches of the 

 meridional canals are mostly blind, and all run toward the mouth, 

 exactly as Moser figures them, and the gastric canals are unbranched. 



