Chap. III. ABACTINAL SYSTEM OF CYANEA. 95 



{Fig. 6, a). The bulging masses between these furrows have, therefore, a rounded 

 surface, but the most bulging part {Fig. 3, between h and c) extends straight, in 

 the direction of the crooked lines and nearer to the long junctions, towards the 

 small lobes. The natural consequence of this is, that the more acute and deeper 

 furrows, along the long junctions {Fig. 7, o), extend more evenly towards the 

 ocular apparatus (o), between the two small lobes, while the more open and shal- 

 low furrows along the short junctions terminate more abruptlj^, the bulging mass 

 rounding off towards the upper surface more suddenly in the direction of the 

 short junctions than in that of the long junctions. Another consequence of this 

 form of the bulging portions of the disk upon the lower surface is, that the 

 spaces which follow the large festoons, or broken lines, inside of the great emar- 

 ginations, are steeply slanting {Fig. 3, u), and this is the more marked, as there is a 

 furrow along the large festoons between the bulging masses and the marginal portion 

 of the disk which forms the large lobes. Though less prominent, there is also 

 a similar depression between the less abrupt termination of the long furrows, and 

 the small lobes ; but this part is further distinguished by small lobes of hyaline 

 substance {Fig. 7, o), of a semi-oval form, hanging vertically upon the two sides 

 of the prolongation of the furrow, in which the ocular tubercle is secured. 



SECTION III. 



THE LOWER FLOOR OF CYANEA AND ITS CONNECTION WITH THE UPPER FLOOR. 



The form of the crooked lines (Pis. IV. and V. Fig. 1) is quite peculiar; in 

 the part nearer the inner circle they are straight, they then bend towards one 

 another in pairs, and diverge again to converge anew, and again diverge to reach 

 the margin, their distance from one another increasing gradually, however, at each 

 curve. To the prominent ridges of the bulging, gelatinous masses, which determine 

 these lines on the lower sui-face of the disk (PI. V*. Figs. 3 and 4), is attached the 

 lower floor, which is otherwise free, with the exception of its connection with the 

 upper floor along the numerous, arborescent ridges (PI. V". Figs. 23 and 24) of the 

 thinner portion of the margin, which indicate the lines of connection between the two 

 floors in that part of the animal. Thus arises the large cavity between the two 

 floors, with its radiating pouches, extending toward the periphery along the short 

 and the long junctions and their numerous branches, ramifying to the edge of the 

 margin. There are, therefore, eight narrow pouches (PI. IV. Fig. 1, o o o" o'") in 

 the direction of the eight long junctions, and eight wider j)ouches (« a a" a") in 

 the direction of the short junctions. Of the eight narrow jjouches, four are in 



