282 CTENOPHORyE. Part II. 



and the digestive cavity itself empty. Under such conditions and in a side view of 



the animal (PL 11. Fig. 18 and Fig. '.tS), the origin of the two lateral andndacral tuljes 



p. gg of one side and the anterior and posterior ambu- 



laeral tubes of the same side may be distinctly 



seen arisnig from an ample common cavity, from 



which arise also, between the lateral ambulacral 



tubes, the still Ijroader coeliac tube of that side, the 



lumen of which, g, is projected like a round hole 



Funnel and ciiymifcrous tubes of upou the Centre of thc cavity. Abovo it, right and 



iDYiA KosEOLA A^j. j^„ ^^^ ^j^^ ^^^^^ ^ ^^^.|.^ ^^ ^l^^ funucl, rlsiug to 



a capsule of the eye-speck. — b eye-speck. — cc circum- ^ g «-^ 



scribed a.oa.-</ ca-lmc aperture. -f tutierolo of the ^|-jp murtilCC OU thc tWO sidcS of thc CCUtral CyC- 



cye-speck. — // forks of the funnel. — g opening of the "^ 



caUac tube.- r eceli.ae tube itself. -S A narrow pro- ppcck, aud fomiing, wllCU projecting OUtward, tlie 



longations of the rows of locomotive flapper.^. — P /2 an- J- ' ° l u o 



terior and posterior ambulacral tubes with the flappers of il'rOC'ular ba"" rOOreSented \W Fit}. 7. This SamC 



/2, — /s A lateral ambulacral tubes with their flajtpers. O O X «/ 



-do internal ramifications of thc ambuLacral tubes. appUratUS miiy alsO IjC SCCU lU FigS. 2 aud 3 Of 



PI. I. In Fig. 3, the outline of the whole system may distinctly be traced in faint 

 outlines, from thc aljactinal pole, the eight chymiferous tubes nearly following the 

 outlines t)f the narrow Ijands in the iirolongation of the rows of locomotive flappers, 

 and the coeliac tul)es running between the lateral amliulaera and projecting beyond 

 the outlines of the digestive cavity. 



All these tuljcs follow the course of the amlnilacra. from the central chj-miferous 

 cavity to the margin of the mouth, where the}- open into a wide, circular tulje 

 encircling the mouth. The tubes are very Avide, and their diameter uniform for 

 their whole length. They may best Ix* seen, and their connection with the oral 

 tube is most distinct, in younger specimens {Fig. (Y magnified and Fig. 7), in which 

 the rows of locomotive flappers do not cover them. They are also distinctly seen 

 in views from the actinal side {Figs. 4, D, and 2^), in which the oral tube encircling 

 the mouth is seen to anastomose with all the ambulacral tubes, or rather the 

 ambulacral tubes empty into the oral tulie. The coeliac tube may be perceived 

 for its whole length through the thickness of the spherosome between the lateral 

 ambulacra in Fig. 2, and to communicate also with the oral tul^e. This anastomosis 

 is particularly distinct in a view from the actinal side {Fig. 4). The course of the 

 fluid contained in this system is somewhat peculiar. The great Avidth of the tubes 

 has reference, no doubt, to the very great size of the digestive cavity ; but as they 

 are capable of great extension and contraction, they readily adapt themselves to 

 the quantity of lluid poured into the cliAmiiferous system from the digestive cavity. 

 There is in this family another striictural adaptation, Avhich makes it possible for 

 the larger digestive cavity to discharge the nutritive fluid accumulated in it more 

 promptly into the chj-miferous sj^stem than this takes place in Pleurobrachia. The 

 chymiferous tubes, instead of folloAving a simple course as in the other Ctenophora^, 



