20 THOS. H. MONTGOMERY, 



and medial aspect of the dorsal lobe, and around the ganglion cells 

 of the ventral lobe; they also occur on the dorsal side of the dorsal 

 brain commissure, where, as Bürger ('90) has shown, the neurilemma 

 is absent. 



b) Cells in the lateral nerve chords, between outer and inner 

 neurilemma; they are similar to ;a), except in being devoid of pig- 

 ment. These are most abundant on the outer side of the chord, 

 where the ganglion cells are wanting. (These cells are pigmented in 

 C. marginatus according to Bürger, '90, fig. 49.) 



c) Cells similar to b), but with smaller, more irregularly angular 

 nuclei, which also stain more deeply (Fig. 11). These cells occur 

 both in the brain and the lateral chords, being situated internally 

 from the inner neurilemma, where they produce a discontinuous layer 

 around the fibrous core, and sparingly in the latter. I may remark 

 here, leaving further details for a following paper, that the fibres of 

 the cells lying beneath the inner neurilemma, produce an outer sheath 

 around at least the proximal portions of the nerve fibres; while an 

 inner sheath of the nerve fibres, as shown by Bürger ('90), is formed 

 by fibres of the cells composing the inner neurilemma. 



There is no doubt that the three modifications of the intracapsular 

 tissue, described here, are closely related ; and their slight dififerences 

 in structure might be accounted for, by their ditierent portions in the 

 central nervous system. 



I have found no evidences of cell division in this intracapsular 

 tissue, nor nutritive particles in the cyto- or caryoplasm, such as occur 

 in some of the other tissues. And since the nucleus contains a pro- 

 portionately small amount of chromatin, it is very probable that this 

 tissue does not possess any great amount of vitality, but rather plays 

 the rôle of a passive supporting substance. 



A very brief description of the intracapsular tissue has been given 

 by Coe ('95); and Bürger ('90) describes it more fully in C. mar- 

 ginatus. 



5) An interstitial connective tissue of the body 

 epithelium, I have been unable to find, tliough Coe ('95) mentions 

 such a tissue (but his fig. 1, tab. 15, to which he refers, does not 

 demonstrate its occurrence). 



in. Lineus gesserensis (0. F. Müller). 

 1) Branched connective tissue cells, with inter- 

 cellular substance. The distribution of this tissue is in general 



