224 CTENOPHOR/E. Part II. 



lengthwise Avitli the tubes, give them a finely .striated appearance, as if they were 

 composed of filaments laid parallel to each other. In the wall of the bulbous 

 forks {Fig. 1-4 f^ f'^) of the axial funnel, these cells trend lengthwise, like meridians 

 of longitude, converging at the two obliquely oj^posite apertures, the anterior and 

 the posterior coeliac openings (i,' C). The only place where this wall yaries from 

 one uniform very thin layer is where it constitutes at the same time the inner 

 wall {Fij. 87 J' 2'^) of the tentacular base ; and there it is of variable thickness, 

 as has already been described. 



The vertical rows of locomotive flappers are entirely superficial. Each row 

 consists of a great numljer of isolated, transverse, comb-like bodies, placed one 

 above the other, and movable, either isolatedly or in regular succession or simul- 

 taneously. Each comb consists of a large number of riljljand-like bristles, slightly 

 arched upward and downward, of which the mitldle ones are the longest, tapering 

 gradually sideways; so that the combs are, properly speaking, crescent^shajDed, with 

 a straight base, the teeth or fringes of which are movable in quick vibrations up 

 and down, independently in each comb, and even independently to some degree 

 in each portion of the same coml), as the middle fringes may be seen to move 

 when the lateral are motionless, and the reverse. But, generally, all the fringes 

 of one comb act simultaneously ; but the motion in all the many combs of one 

 row is successive, so that, when the combs are very active, they seem like waves 

 moving up and down in rapid succession along each vertical row, or like the 

 waving spikes in a corn-field agitated by the wind. Again, the imdulations of the 

 different rows are independent, — sometimes all the rows playing at the same time, 

 at other times parts of the rows, or parts of each row, or parts of some rows, 

 playing independently. Pleuroljrachia moving with the mouth forward, the pre- 

 vailing direction of the locomotive flappers is toward the abactinal pole, while in 

 Bolina and Idyia it is toward the actinal pole. 



The nmnber of teeth or fringes in one of the larger combs may be about 

 fifty ; Ijut they are not equally numerous through all the combs in one vertical 

 row. The combs in the upper parts and in the lower \)Axi» of each row nearer 

 the mouth and the area opposite are gradually shorter and shorter, and contain 

 fewer and shorter fringes, the largest being about the middle of the vertical height. 

 They terminate more abruptly and at a greater distance from the centre on the 

 actinal than on the aljactinal side, where they are naturally prolonged toward the 

 central eye-speck. 



The movements of these flappers seem at first to be identical with those of 

 vibratile ciha ; and one might Ijc tempted to suppose that they are formed by a 

 row of compressed vibratile cells, arranged in such a manner as to bring their 

 ciha in one row, and the cells themselves in such superposition above each other 



