98 



EXPLANATION OF PLATE XI. 



Fig. 1 . One of the larger portions of membrane. This was of a loose texture, floccu- 

 lent on the surface and very elastic. It is represented of the actual size. 

 These portions readily broke when lifted out of the water, and quickly de- 

 composed, even in salt and water. 



Fig. 2. A portion of the more dense membrane, having a smooth shining surface, firm 

 texture, and distinct fibrous structure. 



Fig. 3. A portion resembling a cast of the intestine. 



Fig. 4. A portion showing the fibrous arrangement when torn : magnified two diameters. 



Fig. 5. A small portion from the thinnest margin of fig. 2, showing the direction of 

 the fibres crossing each other nearly at right angles, and with considerable re- 

 gularity. The firmness of texture and membranous character of these por- 

 tions, are owing apparently to this arrangement. Magnified 80 diameters. 



Fig. 6. A portion of fig. 1 , magnified 200 diameters. In this figure, the tangled ar- 

 rangement of the filaments is shown, which characterises all the looser and 

 more fiocculent portions. In some parts the filaments are shown split longi- 

 tudinally. 



Fig. 7. A similar portion, in which the filaments are slightly stretched across the field. 

 The longitudinal splitting and transverse markings of the filaments are dis- 

 tinctly seen. 



Fig. 8. The same characters shown more distinctly, magnified 350 diameters. 



Fig. 9. The transverse markings are here shown to be produced by transverse septa, 

 dividing the filaments apparently into cells, filled with green matter. The 

 transverse splitting of the filaments takes place at these joints. When the 

 splitting takes place longitudinally, the laceration passes through the centre 

 of the cells, which are laid open, and the margins of the laceration have a 

 notched appearance. 



