^U CTENOPHORiE. Part II. 



and along the margin of which the horizontal tubes from the stomachal tube are 

 seen to extend as far as the outer margin of the lateral auricles, without entering 

 into direct communication with the tubes of the tentacular bulb. (See Plate VLLI. 

 Fiff. 6 of my paper in the Memoirs of the American Academy.) 



Parts of the walls of the cells surrounding the central chymiferous cavity, and 

 the main trunks Avhich arise from it, are readily distinguished as fibres, which may 

 be seen to shorten or elongate, and enlarge or contract their cavity. The funnel 

 enlarges on the abactinal side of the Ijody into two distinct branches, forming two 

 bidbs, as in Pleurobrachia, wdth oblique openings forward and backward, on the 

 sides of the circumscribed area, and with the black speck in the centre. This 

 black speck is covered b}' a transparent cap, like that of Pleurobrachia. What I 

 have formerly described as a rmg, extending in the form of narrow tubes along 

 the margin of the circumscribed area, is nothing but the optical eflfect of the 

 thickening of the rising edge which encircles the abactinal area. As to the eight 

 narrow bands converging from the summit of the ambulacral comlxs and supposed 

 to be tubes emptying into this ring, I have ascertained that they are not hollow, 

 but, like similar bands in Pleurobrachia, the direct prolongation of the locomotive 

 flappers foding aAvay as they converge toward the abactinal pole. Their relative 

 position, when converging toward the abactinal pole, differs considerably in the 

 different pairs, the two anterior and the two posterior ones being very near 

 together, almost in the longitudinal axis of the body, while the two lateral pairs 

 are at least as far apart from each other as they are from the anterior and 

 the posterior pairs. The ambulacral tubes are not continuous under these eight 

 bands, and do not communicate here with the central chymiferous cavity; but they 

 communicate with it on the actinal side of the body tlu-ough the tube encircling 

 the mouth, which directly anastomoses with the lateral ambulacral tubes and indi- 

 rectly with the anterior and the posterior ambulacral tubes, through the marginal 

 recurrent tube of the large lobes. The currents arising from the main chymiferous 

 cavity run therefore chiefly through the amljulacral tubes, from the abactinal toward 

 the actmal side of the spherosome, with a small eddy toward the circumscribed 

 area. In the prolongations of the anterior and posterior ambulacral tubes the currents 

 may run to and fro from the tul^e of one of the spheromeres to that of the 

 other, or directly back to the central cavity, or pass through the recurrent marginal 

 tubes of the lol^es into the lateral tubes. In the prolongation of the lateral ambu- 

 lacral tulles the current may pass into the oral tube through the oral anastomoses, 

 or into the large lobes through their marginal tubes ; but the current of the coeliac 

 tubes may also run from the main cavity to the sides of the mouth, and thence 

 through the oral anastomoses into the ambulacral tubes. In the tentacular tulles 



