PERFORATED TAPE-WORMS. 457 



generative pore far down, and included between them posteriorly a 

 comparatively small and very narrow valve-like wedge. 



Although the prismatic form of Tcenia saginata has been fre- 

 quently observed, no one has as yet had an opportunity of investi- 

 gating the head. Yet, from what we know of these malformations, 

 we cannot doubt that these cases are correlated with an unusual 

 structure of the head. As we have already noted (p. 396), it is the 

 six-rayed heads which produce such monstra per excessum. The three 

 angles represent the three radii, which are also expressed in the 

 suckers approximated in pairs. Where the ridges are unequally 

 developed, as in Kiichenmeister's Tcenia from the Cape, the position 

 of the suckers is probably also different. Perhaps the suckers belong- 

 ing to the reduced radius are unusually closely approximated, or are 

 represented by only one, as in the Tcenia with five suckers observed 

 by Gomez (according to Seeger). 



Besides the above malformations, we must also note the forms 

 with perforated joints, the so-called Tcenia fenestrata (Tenia perce). 

 There are tape-worms, some of whose joints are normal, while others 

 are perforated by a larger or smaller hole (Fig. 263). According to 

 Bremser, this results from the rupture of the 

 uterus. The hole is at first small, and always on 

 the upper half of the joint, but sometimes in- 

 creases to such an extent that the greater part of 

 the worm is destroyed. I have in my possession 

 a piece a foot long, in which the median portion 

 has been wholly destroyed, and in which the joints 

 are held together only by their narrow margins, 

 and thus present the appearance of a rope-ladder 

 (Fig. 263, B). A second portion, belonging to 

 another worm, shows, among the 121 joints of FIG. 263. Series of 

 which it is composed, all the stages, from the J oints with perforated 



i^ i , , proglottides (nat size). 



nrst appearance of the perforation to complete 

 destruction (A). What I observe here leads me to doubt whether 

 the plausible explanation of Bremser 1 (who was by no means the 

 first to describe this malformation) be correct. This much at any 



1 Masars de Cazeles (Roux Journ., t. xxix., p. 26), cited by Bremser, regarded 

 the perforated specimens as representative of a distinct species. The first to observe 

 these phenomena, so far as I know, was Goze, who, on p. 347 of his well-known work, 

 notes that, among the "dentate (' zackengliedrigen') worms" (i.e., Tcenia crassicollis, 

 auctt.), "there was one with perforated joints. Some joints had in the middle quad- 

 rangular holes, with delicate ramifications. The joints themselves were quite contracted 

 and deformed. The worm had probably suffered injury at this point, and was beginning 

 to repair it." Colin (Gaz. des k6p., No. 1, 1876) reports of a patient that some time after 

 the expulsion of T. fenestrata normal proglottides again made their appearance. 



