434 Dr. P. Miiller on Philomedusa Vogtii. 



anterior extremity, but there remains here a round aperture in 

 each, serving as a communication between every two adjacent 

 chambers. In this way a sort of annular canal is produced 

 round the mouth at the base of the tentacles. The partitions 

 are seldom seen perforated with holes in other places. Pos- 

 teriorly the partitions are continued, following the longitudinal 

 furrows, to the extremity of the body ; but beyond the stomach 

 they form very inconsiderable projections into the general cavity. 

 They seem to be formed of two lamellae, — at least, when looked 

 at straight from the outside, they appear like two dark stripes, 

 separated by a narrow, pale, intermediate one. 



From their insertion upon the stomach to the beginning of 

 the hindmost third or fourth of the length, the partitions are 

 bounded by a broad, yellowish, moderately opake border, folded 

 in an undulated or frilled manner, of which the margin floating 

 freely in the body-cavity is thickened into pads or cushions. 

 On this margin, about 0*1 millim. in breadth, and which is 

 sharply separated from the frilled portion by a paler line, the 

 ciliary movement is particularly lively; and an abundance of 

 thread -capsules, of twice the length and thickness of those oc- 

 curring in the external integument, are imbedded in it. These 

 twelve frills differ in their anterior and posterior extension, and 

 thus show still more distinctly the bilateral symmetry already 

 indicated in the formation of the mouth, in relation to a plane 

 drawn through the axis of the body and the oral channel. When 

 considered in their posterior extension, the first, third, and fifth 

 pairs (counting from the side of the oral channel) constantly 

 appear to be the longest, the sixth pair is of intermediate length, 

 and the second and fourth are the shortest. The two latter 

 pairs, on the contrary, reach furthest anteriorly, the partitions 

 belonging to them descending only to about the middle of the 

 stomach; the third, fifth, and sixth pairs are inserted at the 

 bottom of the stomach, whilst the two partitions of the first pair 

 form a chamber closed towards the interior above the stomach. 

 I believe that we may regard the thickened margins of the frills 

 as analogous to the mesenteric filaments of the Actinice, which 

 here only exhibit the peculiarity of being attached throughout 

 their whole length. The frills themselves may prove to be the 

 place of formation of the sexual materials, of which I have been 

 unable to find any indubitable traces in numerous animals exa- 

 mined in the course of nearly a year. 



In the larger Actinice the existence of small apertures in the 

 cavity of the body is usually betrayed only by the squirting-out 

 of fine streams of water when the animals are seized ; in our 

 animals these orifices themselves are easily detected. They ap- 

 pear, even to the naked eye, as twelve radiating rows of pale dots 



