On the connective tissues and body cnvities of tlie Nemerteans. 25 



the brain lobes and lateral nerve chords (Fig. 29). The general de- 

 scription just given applies to these. 



b) Those situated within the fibrous core of the brain lobes, and 

 of the lateral chords (Fig. 27). These differ from a) mainly in the 

 smaller size, and more marked irregularity in shape, of their also 

 more deeply staining nuclei; also their cell fibres are thicker, and 

 easily discernible. There is non-continuous layer of these cells around, 

 and a few within, the fibrous core ; and especially in the lateral chords, 

 the fibres of each cell of the peripheral layer, radiate very plainly 

 into the fibrous core, furnishing the greater part of the fibrous ele- 

 ments constituting the latter. 



6) A special interstitial connective tissue of the body 

 epithelium is absent. The few connective tissue elements found 

 in this epithelium, are fibres of the pigmented connective tissue of 

 the muscular wall, which penetrate the basal membrane of the epi- 

 thelium. 



IV. I/ineus lactetis (Grube). 



1) Branched connective tissue cells, with inter- 

 cellular substance. As in L. gesserensis, but the basalmembrane 

 of the body epithelium is relatively thinner. 



2) Pigmented connective tissue cells of the body 

 wall. As in L. gesserensis, but the pigment is less abundant than 

 in the red variety of the latter. 



3) Mesenchym tissue is still more reduced than in the pre- 

 ceding species, for owing to the total absence of noticeable body 

 cavities even in the immature individual, no positive evidences of a 

 true mesenchym are to be found. 



4) The parenchym tissue has apparently the same distribu- 

 tion, as in L. gesserensis. 



5) Intracapsular connective tissue of the central 

 nervous system, as in the preceding species. 



6) A special interstitial connective tissue of the body 

 epithelium, is also absent in this species. 



y. Amphiporus glutinosus Vekr. 

 1) Branched connective tissue cells, with inter- 

 cellular substance. Produces the basal membrane of the body 

 epithelium, the outer and inner neurilemma, the intermuscular layers 

 of the proboscis and of- the body wall, the layer immediately beneath 



