389] PSEUDOPHYLLIDEA FROM FISHES— COOPER 101 



very closely with that of Scott (1909, Fig. 3, PL V). However, from the fact 

 that he records B. scorpii as having been found in Anguilla vulgaris, it is quite 

 possible that he had in reality B. claviceps (Goeze) which has been found only 

 in eels up to the present, so far as the writer is aware. 



Segmentation begins immediately behind the scolex, so that there is no 

 true neck. The base of the scolex, nevertheless, has the appearance of a very 

 short neck region from which the foremost segments are cut off as soon as they 

 form. Such in fact is considered to be the case. The anterior part of the 

 strobila on the other hand serves the purpose of a neck in that it shows a divi- 

 sion into subsegments in a manner to be presently described. As regards the 

 habit of the whole strobila and the general shape of the segments, Rudolphi's 

 (1810:51) description of the species is so appUcable to this form that it is 

 given verbatim: 



"Co//mw nullum. Corpus planum, margine crenato. .<4r/JcM/i capiti proxi" 

 mi plerumque longissimi, angustissimi, subcuneati, margine postico untrinque 

 parum exstante, saepe tamen, praesertim post mortem, contract!, ut reliquis 

 vix longiores appareant. ArticuU insequentes anticis breviores et sensim 

 latiores; postici subaequales, fere quadrati, ut plurimum latiores quam longi, 

 interdum quasi ex duobus tribusve confusis compositi, satis magni, margine 

 obtusiusculo hinc inde inciso. Articulus ultimus obtusus. 



Linea utrinque longitudinalis articulos majores percurrit. Inter utramque 

 faeturae apparatus. " 



Leidy (1855:444) described the strobila of the B. scorpii which he found in 

 Plaksa plana as foUows: "Neck none. Anterior segments cuneate or tri- 

 angular; posterior ones quadrate; each with an appearance of three subdivisions, 

 with the subsegments having a pair of generative apertures, in the course of a 

 longitudinally depressed dark colored line, passing the length of the body." 

 Cobbold (1858:157) said of individuals from Cottus bubalis: "Toward the lower 

 part of the so-called neck, the joints exhibited at the lateral margins indications 

 of division, which became gradually more defined towards the tail. " In the 

 same connection Krabbe (1865:37) stated that, according to Eschricht, "Pen- 

 dant leur developpement ulterieur, I'augmentation du nombre des articles n'est 

 pas toujours exclusivement due, conune chez les Taenias, a la formation de 

 nouveaux articles engendres par la tete, mais chez quelques especes, telles que 

 les B. dubius, variabilis et fasciatus, [here B. punctatus also] elle est encore 

 produite par la division transversale qui s'opere dans les articles deja formes. " 

 Olsson (1867:55) also referred to multiplication of segments by transverse 

 division of older ones. Loennberg (1891 :52) denied this statement of Olsson's, 

 but, as pointed out below, the negation is applicable to the posterior mature seg- 

 ments of this form at least, not to the middle segments referred to by the 

 latter. Linton (1890:773) said "Secondary segments appear at about 

 the twelfth segment from the head. These are formed by a division of each 

 segment into two by means of a median transverse Une. This is repeated far- 

 ther back in much the same manner as described under D. microcephalutn." 

 In this form such subdivision of segments to form daughter segments occurs 



