744 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [26] 



ous (?) vessels. The body, indeed, can not be said to be distinctly seg- 

 mented. 



The water vascular system at this point consists of four principal 

 vessels, situated in pairs, each pair lying on the inner side of what I 

 take to be a lateral nervous vessel. The diameter of the aquiferous 

 vessels is from .013 to .027 mm . The two nervous vessels are larger, 

 being from .027 to ,054 mm in their longer, and slightly less in their 

 shorter diameter. Each of the latter is flanked on the sides next 

 the lateral faces by two other small vessels which appear to be of the 

 same nature. No nucleated cells were observed at this point in these 

 vessels, but they contain a net-work of connective tissue, some of the 

 meshes of which are filled with finely granular substance, while others 

 are empty. 



An oblong, central part of these sections has the two nervous ves- 

 sels at its extremities; in it also lie the aquiferous vessels, with an 

 occasional transverse vessel. This central space has a few transverse 

 fibers crossing it, but is made up for the most part of fine connective 

 tissue in which are numerous small cells which are deeply stained with 

 carmine, averaging about ,003 min in diameter, and each containing several 

 dark granular specks. These cells are quite different in appearance 

 from the cut ends of longitudinal fibers, and present the same appear- 

 ance in both transverse and longitudinal section. Moreover, the cen- 

 tral core does not show longitudinal fibers in longitudinal sections. 

 Granular cells, similar to the -above, are scattered pretty generally 

 through the tissues. 



The longitudinal muscles of the body are arranged in four principal 

 bands, two lateral and two marginal. These muscles are very strongly 

 developed. Outside the four bauds of longitudinal muscles is a layer 

 of circular muscles with radiating and longitudinal fibers interspersed. 

 - A longitudinal section shows the lateral nervous canals to be some- 

 what irregular in diameter and without definite walls. They pursue, in 

 the main, an undeviating course, while the aquiferous vessels, which, 

 with reference to the nervous canals, lie towards the center of the body, 

 have a pretty uniform diameter, and pursue an irregularly spiral 

 course. A few nucleated cells were observed in the nervous canals. 



Further investigation is needed to demonstrate the exact nature of 

 vessels which I have called nerves. 



Anatomy of the proglottides. — Sections made near the posterior end 

 of one of the longest strobiles show an outer, dense granular layer in 

 which are numerous very fine circular fibers with a few radiating fibers. 

 Within this layer, which is about .l mm thick, is another layer of very 

 powerful longitudinal fibers. These occur in fascicles averaging ,027 mm 

 in diameter. This layer is limited on both sides by a thin layer of cir- 

 cular fibers ; it is complete except at the two margins, where there is a 

 short interval where longitudinal fibers are wanting. 



The reproductive openings are marginal, about the middleof theseg- 



