128 



DESCUirTION OF THE PLATES. 



Fig. 89. End view of tho same as firj. 88. 



Fiq. 90 (150 diam.). A combined longitudinal sectional and surface view of a part of the shaft 

 of a tentacle. At n' tBe opsophragma is in profile, and at 1»' it is presented as scon at the surface, 

 extending partly across the field. At l«r the opsomyoplax is in profile, and at 2»r; 3)h' are the 

 fibrils of the same, nearer the eye, underlying the opsophragma (bi") and overlying the chondromyo- 

 pla.x {V) and the gastrophragma (Ir) in the distance. Next within the muscular layer lies the 

 chondroniyoplax, which is seen partly in section (at 6'), and a small portion at the exterior surface 

 (65) as it curves over and rises, toward the observer, from the distance. The innermost wall 

 (gastrophragma) is seen, also, partly in profile (f) and partly at the surface (If'), the cells being pre- 

 sented endwise. 



Fin- 91. Transverse section of _/?;/. 90, representing a little more than a quadrant of the cylinder. 

 At ni' tlic muscular fibrils are cut across. The wedge-shaped character of the cells of the gastro- 

 phragma (r), as they diverge from the central cavity (f'), is quite evident. 



Fig. 92 (T50 diam.). Face view of the cells of the outer wall (</) and the underlying muscular 

 fibres {m-), to show the linear arrangement of the former when the tentacle is contracted. 



Fig. 93. Prolile >t^ Jig. 92, to compare with the cells of the same wall (in fig. 90, n') when the 

 tentacle is extended. 



PLATE IX. Fifjures 94 to 108. 



Fig. 94 ('r.50 diam.). The innermost wall (gastrophragma) of the anchor of a three-quarters grown 

 animal, exhibiting its enormous thickness at one part (B), and its gradual thinning out (A to D) ; 

 as well as the great masses of pigment ((Z-) in the cells. 



Fig. 95. Face-view of tho same as fig. 94. 



Fig. 9G (350 diam.). The outer wall and the imbedded colletocysts (a) of an anchor. At a} the 

 pit in which such as o are sunken. 



Fig. 91 (150 diam.). More highly magnified views of a part of the same as fig. 9f) ; a part of the 

 cells are omitted so as to expose more clearly the structure of the colletocyst (o), particularly its 

 clear periphery (fr). 



Fig. 98 (115 diam.). A combined surface and longitudinal sectional view of a digitulus and a 

 genital sac. At A and B the opposing flat sides are seen edgewise, meeting along the midline of 

 the figure ; at A, distinguished by the crowded colletocysts, and at B and C, by the nematocysts. 

 At D is a section of the thickness from face A to face B. The mouth (s'^) of the genital sac is quite 

 wide open. 



Fig. 99 (550 diam.). The colletocystic side of a portion o^ fig. 98, partly at the surface (Iffl) and 

 partly so as to expose the underlying muscular fibrilke (A) and the layer of colletocysts in profile (at a). 



Fig. 100. Transverse section of the same as fig. 99, displaying on one side the nematocysts {I), 

 and the very long vibratile cilia (co), and on the other the crowded layer of colletocysts (a). 



Fig. 101 (150 diam,). More highly magnified view of a part of tho adjoining nematocystic {I) 

 and colletocystic (a) faces of the same as fig. 98. 



Fig. 102 (150 diam.). Colletocysts with the periphery drawn out to various lengths (a'). 



Fig. 103 (350 diam). A part oi fiig. 99, after treatment with fresh water ; the colletocysts adhe- 

 rent after the cells of the wall have fallen away, and exposed the fibrilte (7() of the gastromyoplax. 



Fig. 104 (150 diam.). Some gastrophragmic cells (i) and fusiform fibrils (/•') of the muscular 

 layer at the point where it passes into the cords of the peduncle. 



Fig. 105 (150 diam.). The innermost wall (gastrophragma) (z^) lining two adjoining, nearly 

 completed, irregular passage-ways between the tubes of the peduncle. Near A, new cells are forming 

 between B and C, pushing their way through the solid mass of chondrophys (c'), and eventually 

 becoming tho face-wall of the passage (r'), hero in process of excavation. 



Fig. 106 (350 diam,). Face-view of the fibro-cellular chondrophys of a very young specimen 

 {fig. 82). 



Fig 101- Profile of one of tho fibro-ccllular elements o^fiig. lOG, taken near the thinning edge of 

 the chondrophys (see figs. 82, 83). 



