395] PSEUDOPHVLLIDEA FROM FISHES— COOPER 107 



posterior end of the body the adult segments are arranged in groups of from 

 four to six simple segments, as if the latter were partially fused together, which 

 is another characteristic of this species. " From these statements and the 

 further fact that the posterior proglottides have been described as trapezoidal 

 (Stossich), quadrate (Rudolphi, Linton), subquadrate (Diesing), or at most, 

 broader than long (Rudolphi) — actually about twice as broad as long from 

 Linton's (1890:732, 734) description — it is evident that the groups of four 

 sets of reproductive organs (much less frequently three, five or six) shown here 

 in figures 59 and 60, and separated from each other by grooves which in al- 

 coholic material appear to be complete, have been considered to constitute 

 the ripe proglottides. But, as pointed out by Lonnberg, the lesser transverse 

 furrows are only "greater WTinkles or foldings of the surface" and do not cut 

 in deep enough to cause the parts immediately ahead to stand out distinctly 

 like the posterior borders of the proglottides of other species, e.g., C cras- 

 siceps. Such posterior borders, with their accompanying "complete" trans- 

 verse furrows, do occur, however, but only at considerable intervals. One case 

 is shown in figure 95, where it will be noticed there is no such distinct separation 

 of the proglottis from the next one ahead. So far as the writer is aware, this 

 has been pointed out only by Luhe (1910:25) who said: " ... in reifen 

 Gliederstrecken Uegen zwischen zwei vollig durchgehenden, aber auch nur 

 wenig hervortretenden oberflachUchen Querfurchen in der Reg el 16 sehr kurze 

 Genitalsegmente, die ausserlich voneinander nur durch Zackenbildungen des 

 Seitenrandes gescheiden sind. " In this connection it should also be noted 

 that in his description of Fimbriaria fasciolaris (Pallas), a taenioid from various 

 water birds, Wolff hiigel (1900:94) remarked that it is com.parable to B. scorpii 

 in that "eine bis ins aussergew*^ hnhche gestiegerte Anzahl von Geschlechts- 

 apparaten in einer Proglottis sich folge. " 



In a considerable length of one toto mount of this form there were found 

 ahead of and including the region of differentiation of the reproductive rudi- 

 ments the following consecutive number (from behind forwards) of genital 

 segments between the most pronounced transverse furrows, that is in the 

 primary segments in question: 67, 82, 101, 107, 90, HI, 116, using as the cri- 

 terion of a genital segment, especially ahead of the region of differentiation, 

 the aggregation of nuclei in the median line which will go to form the central 

 organs and ducts of the sytem. There is, however, much difficulty in making 

 these counts on account of rudimentary or intercalated groups of nuclei which, 

 judging from conditions to be seen in the region of differentiation, may or may 

 not form complete sets of genitalia, and above all of the further subdivision 

 of many of these rudiments, which otherwise proceeds in quite the same man- 

 ner (Fig. 57) as that of the external segments in the anterior part of the strobila. 

 Furthermore, there may often be seen either in the anterior part of the 

 region of differentiation or miuch farther ahead (Fig. 57) a lateral doubling 

 of the developing genitalia. But since no case was met with of two sets of 

 reproductive organs in a ripe genital segment, it was concluded, especially 

 because of the great infrequency of this dupHcation, that one or the other rudi- 



