OX CTEXOPIIORES OF THE NEIGHBOURHOOD OF MISAKT. 453 



of 1 91 7, contain a number of Cercariae in the jelly of the body. The 

 Cercaria^, apparently all of the same species, are provided with a pair 

 of eye-spots and a tail bearing long setae. 



Remark. — MOSER described the ctenophore in question as a new 

 species under the name of H. japonica holding it distinct from the 

 Atlantic H. palmata. According to that authoress, the Japanese form 

 should differ from the species just mentioned, chiefly in the length of 

 ribs and meridional canals, and in the configuration of tentacle-basis. 

 It was given by her that in H. japonica the ribs are considerably 

 shorter than the meridional canals, which latter stop some distance 

 short of the margin of mouth, and that the tentacle-basis describes a 

 simple curve, so that its middle point, whence issues the stem, is 

 situated farthest away from the pharyngeal vessel. In H. palmata, on 

 the other hand, the ribs and meridional canals should be nearly equally 

 long, and both should reach down very close to the mouth ; the 

 tentacle-basis should present a double curvature, placing its middle 

 point very close to the pharyngeal vessel. However, BlGELOW found 

 (191 2, p. 381), after careful examination of the characters referred to, 

 that these are subject to much variations and do not form decisive 

 differential criterion between the two forms in question. So far as 

 concerns the tentacle-basis, my observations on the Japanese material 

 stand decidedly in agreement with Bigelow's view, inasmuch as I have 

 found that structure to be sometimes simply curved and at other times 

 doubly curved or to run nearly or quite straight in different individuals. 

 With respect to the length of ribs and meridional canals, the material 

 before me conform to Mosers account rather than to BlGELOW's, the 

 ribs being very much shorter than the canals and the latter ending 

 distinctly short of the mouth margin. Under the circumstances and in 

 view of the very close agreement in all other respects of structure, I 

 deem it advisable to unite the Japanese and Atlantic forms 'under one 

 species, though a more extented knowledge than we have at present 

 concerning the latter may possibly necessitate making racial distinction 



