22 8 NATURAL HISTORY BULLETIN. 



due to the almost complete loss of the ectoderm in the Iowa 

 University specimens, the white mesoglcea being exposed. 



The base in both sets of specimens is slightly less in diameter 

 than the column and appears to have been but feebly adher- 

 ent. Its diameter in the specimens from Station 29 was 1-1.5 

 cm., the height of the column in the same specimens varying 

 from 1.5 cm. to 2.5 cm. The single specimen from station 

 64 had, however, much greater dimensions, its base measur- 

 ing nearly 2 cm. in diameter while the height of its column 

 was 4 cm. A figure of this specimen of about natural size is 

 given in PL 1, Fig. 1. 



As a supplement to the original description I give a couple 

 of figures from the present specimens. PI. 1, Fig. 2 shows 

 the absence of a sphincter muscle and also the sudden cessa- 

 tion of the thickness of the column mesoglcea just at the bases 

 of the tentacles, a distinct parapet being thus formed. The 

 nematocysts found in the ectoderm of the Fish Commission 

 specimens could be seen in the present forms in the few 

 patches of ectoderm which persisted and seemed to be espe- 

 cially abundant at the edge of the parapet. The ectodermal 

 musculature of the column was also visible, though with con- 

 siderable indistinctness owing to the extensive maceration which 

 all the specimens had suffered. The tentacles in the speci- 

 mens from Station 29 seemed to be about forty to forty-five 

 in number, but in the large specimen I counted fifty-four and, 

 allowing for a portion of the margin which was injured, the 

 total number must have been over sixty. 



The preparation from which Fig. 3 was drawn was a trans- 

 verse section through the upper part of the column of one of 

 the smaller specimens from Station 29, and is given for compar- 

 ison with Fig. 14, PL xxi of my Fish Commission report ('93). 

 The general structure of the mesenteries and their muscula- 

 ture were the same as in the Fish Commission specimens, al- 

 lowance being made for the difference in size and probably 

 therefore of age of the two examples. Ten pairs of mesen- 

 teries were present, but, although some of the mesenteries 

 were smaller than others, I could not make out any definite 



