14 THOS. H. MONTGOMERY, 



anastomosing fibres produce a plexus around the epithelial cells- 

 apparently none of these fibres penetrate into the basement membrane. 

 The nucleus is oval, with a large amount of chromatin; around it is 

 a cytoplasmic mass, from which the fibres are given off. There is no 

 pigment present in this tissue, the pigment of the epithelium being 

 situated in the supporting cells, as shown by Bürger ('90). 



II. Ceréhrattilus lacteus Verrill. 

 The "gelatinous tissue" and "parenchyma cells" have been briefly 

 referred to by Coe, in his recent paper ('95) on the anatomy of this 

 species. The connective tissue elements have been more minutely 

 delineated by Bürger ('90), for other species of the genus. 



1) Branched connective tissue cells, with more or 

 less dense intercellular substance. This tissue has the 

 same distribution as in Carinella, but is apparently absent in the 

 inner longitudinal muscle layer of the body wall — or at least is 

 present around only the more externally situated muscle fibres of the 

 same. The cell (Fig. 13 C l) is multipolar, its fibres branch and 

 anastomose. The elongated, often spindle shaped nucleus, stains very 

 deeply, and is situated in a cytoplasmatic envelope, which stains in- 

 tensely with eosin, often presenting a refractive appearance, but 

 which contains no easily discernible granules, such as we found in 

 the cells of Carinella. The homogeneous intercellular substance (I.S) 

 stains slightly with haematoxylin, and seems denser than in Carinella ; 

 also the number of the cells is proportionately smaller, and the amount 

 of the intercellular substance greater than in that genus. The fact 

 of the proportionately small number of nucleated cells, and the 

 frequent evidences of cell degeneration, would show that in Cere- 

 hratulus this tissue is much less alive, if I may be allowed the ex- 

 pression, than in Carinella. After the degeneration of the cells just 

 mentioned, their fibres still remain in the intercellular substance. 



2) Mesenchym tissue. The fact that the specimen of this 

 species which I studied, was an immature individual, of about six or 

 seven inches in length, may account to some extent for the discrepancy 

 in my results, and those of Coe. Thus this investigator writes ('95, 

 p. 485) : "It is not uncommon to find a small split between the outer 

 border of the intestinal caeca and the surrounding gelatinous tissue. 

 In some species of Nemerteans this split is stated to be lined with 

 a special membrane, although in this species it could not be found, 

 the split appearing merely as an artificial shrinking of the intestinal 



