467] PSEUDOPHYLLIDEA FROM FISHES— COOPER 179 



Linstow included in his conception of the cuticula not only the cuticula 

 proper, which he stated was ?>.Zn in thickness, but also the outer clear zone of 

 the subcuticula which he found to be 49/i thick. In the present study the 

 cuticula was found to be about Sju thick and to be divided into the three zones 

 described by Lonnberg; viz., an outer pseudociUated or ragged layer, occupying 

 almost one-half of the thickness of the whole membrane, a middle homogeneous 

 principal stratum, and an innermost basement membrane which stands out 

 quite distinctly in this species without the use of any special stains. The sub- 

 cuticula was found to average 0.14mm. in thickness, the clear outi'r ends of 

 the elongated cylindrical and closely crowded cells being collectively 23)U thick. 

 The whole cortex in transverse sections has a depth of 0.32mm. Small cal- 

 careous bodies, quite difficult to distinguish from parenchymatous nuclei, are 

 present as described and figured by Lonnberg. They are oval to elliptical 

 in outline and have a maximum length of IQy.. 



The musculature is well developed, and is peculiar in that the sagittal fibres 

 especially retain their myoblasts, which are very easily recognized in sections. 

 "They extend from the dorsal to the ventral surface and are usually attached 

 to the cuticula with their ends, but often fasten on to the walls of the excretory 

 vessels or other organs. Their number rises considerably with increasing age 

 of the proglottis. Since they pass thru the spaces between the bundles of 

 longitudinal muscles, they are partially arranged in fasicles. These muscles 

 have not only a nucleus, but often also surrounding the same a quite large, 

 spindle-shaped protoplasmic mass; and one easily finds the different develop- 

 mental stages from a spindle-shaped cell to fully developed muscle fibres of 

 typical appearance, where the protoplasm is already transformed and reduced, 

 and only the nucleus persists. " They are only slightly more numerous between 

 the sets of reproductive organs than elsewhere. In tliis region, on the other 

 hand, the transverse series form, as emphasized by Lonnberg, a distinct parti- 

 tion separating all constituents of the genitaha of successive proglottides,the 

 testes and vitelline follicles especially (cf. A. crassum). In transverse sec- 

 tions they form a "plate," bounding the medulla externally on each surface, 

 from which a few fibres pass farther out among the bundles of longitudinal mus- 

 cles. The latter are arranged in two distinct layers, each about 0.15mm. in 

 thickness in the median line, which gradually diminish towards the edges of 

 the strobila where they join thru several small and very irregular bundles. 

 These larger fasicles are further subdivided dorsoventrally into smaller ones 

 of various sizes, aU of which are connected longitudinally, however, by strands 

 passing from one to the other, as pointed out by Lonnberg. In the anterior 

 end of the strobila, as one foUows them forwards, the fasicles of longitudinal 

 fibres become less and less distinct, but extend to the tip of the scolex, or young 

 pseudoscolex, as the case may be, scattering considerably as they go. In 

 sections thru the structure shown in figure iZ, a small number of sagittal and 

 transverse fibres and a very few radial ones, situated between the grooves seen 

 externally proves that it is a scolex, but a poorly developed one, or, as indicated 

 above, one showing early stages in the process of degeneration to form the 



