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PROCEEDINGti OF THE NATIONAL MUSEUM. 



Vol. 4!S, 



four times. The outermost branching is close to the margin of the 

 stomach and is obscured by the lips. In the type there are 38 canals 

 resulting from the bifurcating of the four primary ones. 



As a result of this method of branching, the canals arc in groups. 

 The number of groups varies according to the number of branchings 

 which each main stem has undergone, and the number of canals varies 

 from group to group. In the type the "cross" is so irregular that it 

 is hard to determine which trunks are the four primary ones. But in 

 another specimen, in which the features are more regular, there are 

 10, 5, 7, and 7 canals, originating from each of the four primary trunks, 

 respectively. In another there are 9, 12, 5, and 8. In the two 

 young ^quorids described by Maas, which probably belonged to this 

 species, the central cross is quite regular, and in each specimen there 

 are 32 definitive canals. 



The canal-stripes within the limits of the stomach are the visible 

 evidence of lines along which the upper (outer) wall of the manubrium 

 is now attached to the subumbrella. Between these lines it hangs 

 loose, leaving spaces into which a probe can be inserted, or an air bubble 

 injected. Consequently it is easily stripped off, and all the specimens 

 show more or less damage of this sort. Maas doubts whether the 

 conditions in his specimen, which are essentially similar to those here 

 outlined, are to be explained as the result of the branching of primary 

 simple canals, or whether the numerous canals arise directly from 

 the base of the stomach which grows laterally sinously ("sinos"). 

 The complexly branched figure seems to indicate the former. The 

 difference between these two concepts is more apparent than real, for 

 the specimens show that the "branching," that is, the growth of new 

 centrif ugally formed canals, takes place from the margin of the manu- 

 brium at the points whence the preexisting canals emerge from it. 

 The manubrium itself broadens as so many sinuses along the suc- 

 cessively formed canals. A still further specialization would be 

 branching of canals outside the margin of the manubrium, such as 

 Haeckel has described. 



Marginal organs. — The numerical relations of tentacles and canals 

 and the proportional size of the stomach are given in the table for 

 seven specimens : 



