469] PSEULOPHYLLIDEA FROM FISHES— COOPER 181 



that they are usually quite flattened anteroposteriorly. Linstow gave the 

 diameter as 0.06mm. As stated by Lonnberg, they show various stages in the 

 development of spermatozoa quite well. Altho Linstow described them as 

 being arranged in an elongated half-ring on each side, they were found by the 

 writer to occupy all parts of the medulla in the fields indicated, interminghng 

 irregularly with the vitelhne foUicles, but in general more numerous in the 

 median frontal plane. From 23 to 30 are present in each lateral field, thus 

 making the total number for the proglottis from about 45 to 60. The vas 

 deferens forms an elongated mass of coils in the anterior portion of the proglot- 

 tis, which extends from the uterus-sac to the cirrus-sac, near which its coils are 

 fewer in number and more openly arranged. The whole mass has a length 

 (transversely) of •0.35mm. by a diameter (longitudinally) of 0.07 to 0.08. As 

 pointed out by Liihe (1900a) the duct forms within the cirrus-sac a proximal 

 winding ductus ejaculatorius — it is often quite dilated — and a distal straight 

 cirrus proper, which occupies half the length of the sac. The cirrus-sac varies 

 in length from 174 to 277iJ, and in maximum diameter, medially, since the whole 

 is ovoid with the narrow end outward, from 92 to 102/x. Liihe gave the mea- 

 surements as 220 by 75 to 90;:. As noted by the same vmter, myoblastic nuclei 

 form such a thick layer outside of the wall and there are so many parenchy- 

 matous nuclei within the sac, that the wall itself is at first difficult to locate in 

 sections. The cirrus proper may have a dorsoventral diameter of 40/:. 



The vagina has a diameter of 20ju as it passes the cirrus-sac, and is lined 

 with a comparatively thick cuticula. Liihe stated that the ventral bow in its 

 course is more median than in A. crassum, but in the material sectioned the 

 very reverse was found to be the case. The ovary of this species is very con- 

 spicuous since it is large (0.6mm.) wide compact and somewhat kidney- 

 shaped; Linstow's measurements are 0.14mm. wide by 0.12 long. There is 

 no distinct isthmus, or, as Lonnberg stated, there is a very broad one, both 

 longitudinally and dorsoventrally, from the middle of the anterior face of 

 which the oviduct arises either towards the dorsal or the ventral surface. The 

 ova are large and conspicuous because of their prominent nuclei which are 

 from 10 to 13/i in diameter, while their nucleoh are about 2.5/x. Linton (1890: 

 752) gave these data as 8 to 14 and 2.5/:, respectively. The oocapt has a dia- 

 meter of about 34/t. From it the oviduct proceeds laterally at first, then with 

 a sharp turn back, i.e., "towards the side opposite the genital-opening," it is 

 joined by the vagina just before it makes a second turn towards the dorsal 

 surface of the proglottis (Fig. 109). The viteline follicles are, as stated by 

 Lonnberg, entirely within the parenchymatous muscle-sac — and thus 

 discontinuous longitudinally — altho Liihe (1910:26), probably basing his 

 statements on Matz's (1892:113) description, said that they are "... zum 

 Teil noch nach inner von der Langsmuskulatur. " They are arranged in two 

 lateral fields corresponding to those occupied by the testes with which they 

 intermingle freely, altho being situated more peripherally. They are somewhat 

 irregular in shape and size, but usually compressed anterposteriorly, and as 

 much as 90/: wide, 30 long and 70 thick. There is a m.edian field free of them 



