22 A FLORA WITHIN ANIMALS. II. 



herbivorous coleopterous insect, Passalus cornuhis, resembling very much in its 

 habits the Julus marginatus, and like it, living in decaying stumps of trees, I found 

 a constant and most extraordinary profusion of vegetation, only equalled by that of 

 Julus marginatus, among which was the third and very graceful species, the Entero- 

 bryus attenuatus. 



1. Of the Principal Cell of Enterobryus. (P\. I. Fig. 1, I; 3, 6; 4, c.) This 

 is a very long, tubular, cylindrical cell, closed at the extremities. The end 

 attached to the pedicle is set or received into a concavity, and is usually slightly 

 dilated beyond the general diameter of the cell. (PI. III. Fig. 11, a.} The distal 

 end is usually more or less dilated or clavate and obtusely rounded (4), or it is 

 abruptly truncated (17). 



In Enterobryus attenuatus (PI. I. Fig. 3) the cell is sometimes narrowed from the 

 middle towards both extremities; at other times from the sigrnoid flexure towards 

 the distal end ; but frequently is nearly uniform in its diameter throughout. 



The cell-wall is amorphous in structure, thin, coriaceous, strong, flexible, very 

 slightly elastic, perfectly transparent, usually colorless always so in yftung speci- 

 mens frequently amber-colored, or yellowish or brownish, and occasionally dark 

 brown. Its thickness is pretty uniform, except at the extremities, where it is 

 rather thicker than at the sides. Its usual average is about the --fa-$ of an inch. 



In E. attenuatus, the cell-wall is sometimes twice as thick at the sigmoid flexure 

 of the thallus as elsewhere; in the former position measuring the ^0r f an 

 inch, in the latter the -jTrtarir of an inch. When the distal extremity of the 

 principal cell has no secondary ones attached, and is truncated, the cell-wall form- 

 ing the margin of the extremity is increased in thickness sometimes to a triple 

 extent, and occasionally projects beyond the general outline of the cell (PL III. 

 Fig. 17, d). In these latter cases, the cell-wall forming* the terminal face of the 

 truncated extremity of the cell is sometimes so very thin that it appears as if the 

 permanent cell-wall ceased at the margin of the extremity, and the internal, very 

 delicate, transparent, colorless, mucoid bounding layer between the permanent cell- 

 wall and the cell-contents, or the primordial utricle of Hugo von Mohl, protruded 

 from the open end, resembling the crystal upon the face of a watch (PI. II. Fig. 4, 6; 

 III. 7). Generally, however, it is observed that the cell-wall at the truncated ex- 

 tremity, though thin, is sufficiently strong to prevent the appearance described. 

 In those cases in which the distal end of the principal cell of Enterobryus is clavate, 

 with or without attached secondary cells, the cell-wall is thicker at that than at 

 any other portion of the cell. 



The cell-contents consist of a hyaline, or occasionally a faint amber-colored 

 mucoid or albuminoid fluid, or protoplasma, with granules and globules of various 

 sizes (PL III.). 



It is only in the youngest individuals of Enterobryus that the principal cell 

 usually contains a large quantity of the protoplasma. Ordinarily, at all more ad- 

 vanced ages, it is distended with fine and coarse granules and large globules, the 

 intervals only being occupied by a relatively small proportion of protoplasma. 



