CONNECTIVE TISSUE, 179 
very closely resembles the epithelial tissue, except that 
the intervals between the nuclei are wider, and that the 
substance in which they are imbedded cannot be broken 
up into a separate cell-body for each nucleus. In the 
second form (fig. 51, A) the matrix exhibits fine wavy 
parallel lines, as if it were marked out into imperfect 
Fig. 51.—Astacus fluviatilis —Connective tissue; A, second form; B, 
third form. «, cavities; n, nuclei. Highly magnified. 
fibres. In this form, as in the next to be described, 
more or less spherical cavities, which contain a clear 
fluid, are excavated in the matrix; and the number of 
n2 
