CERIANTHARIA. 



break in this increase of the length in the mesenteries. In Me. Murrich's figure this break occurs 

 at the 3rd and 5th quartette. In one of the specimens examined by me however, this was not so 

 clear, as the 4th metamesentery of the ist cycle was a little shorter than the 3rd. My specimen 

 also suggests the inference, that possibly a further break occurs at the 7th group in larger specimens. 



As regards the metamesenteries of the and cycle, there is no sign of such an increase of length 

 in the mesenteries towards the multiplication chamber, nor yet is this the case with the metamesen- 

 teries of the 3rd and 4th cycles. The mesenteries of the 2nd cycle decrease towards the multiplication 

 chamber according to my observations; in the 6th quartette according to my terminology a break 

 first occurs, so that we there find a mesentery as long as or longer than that in the 5th group. The 

 mesenteries of the 3rd and 4th cycles stand in much the same relation. Here too breaks occur, but 

 because these mesenteries do not extend far below the stomatodaeum and because of their contraction, 

 I cannot definitely state whether this break takes place at definite quartettes. However it appears 

 as though the mesenteries of the 3rd and 4th cycles were distinctly feebler in the ist than in the 

 2nd quartette. Very probably variations in proportionate length between the different quartettes occur 

 in the mesenteries of the 2nd as well as of the 3rd or 4th cycle, but to investigate this closely 

 access should be had to fully extended specimens in the very best preservation. Presumably also 

 the cnido-glandular tracts of the mesenteries of the 3rd and 4th cycles in the quartettes lie at regular, 

 though varying distances from the lower border of the stomatodaeum, but this cannot be clearly 

 determined with contracted specimens. 



The metamesenteries of the 2nd cycle compared with those of the ist are short Their free 

 border is about twice as long as in those of the 3rd and 4th cycles. But an exception occurs in 

 the first metamesentery of the 2nd cycle (Protomesentery 4, Me. Murrich) which is the longest me- 

 sentery of this category and attains a length of about half the free border of the longest mesenteries. 

 The metamesenteries of the 3rd and 4th cycles are short, and their free border below the stomato- 

 daeum is not more than the length of the stomatodaeum. 



As regards the subdivision of the filaments, there are found, as regularly among the Cerian- 

 tharia, both ciliated tracts and cnido-glandular tracts in all metamesenteries. In addition, on all meta- 

 mesenteries are also found craspedonemes (called in Me. Murrich's first work 1890 acontia) and in 

 the metamesenteries of the ist and 2nd cycles and in protomesenteries 2 craspedia as well. 



The subdivision of the filaments in the metamesenteries of the ist cycle (M) agrees with that 

 found in protomesenteries 2. The same is the case with the metamesenteries of the 2nd cycle (m)\ 

 the cnido-glandular tract however is more developed in these mesenteries. Those of the 3rd cycle (B) 

 resemble, as to the filaments, those of the 2nd, but have a more developed cnido-glandular tract. The 

 mesenteries of the 4th cycle (b) have a specially well developed cnido-glandular tract but feeble 

 craspedonemes in the region of the ciliated tracts, which in this case is very short. 



The structure of the filaments agrees in the main with that found in C. membranaceus. In 

 the upper part of the region of the ciliated tracts, the median streak (spirocyst-glandular tract) is 

 divided into 2 parts separated by a more undifferentiated part (median streak Me. Murrich 1910). 

 The lateral portions of the median streak shew the typical structure, i. e. they contain numerous thin- 



Thc Danish Ingolf-Expcditiou V. 3. 4 



