106 ILLINOIS BIOLOGICAL MONOGRAPHS [394 



exhibent ; in superficie autem ventrali nodulus simplex vel duplex, pariter, sed 

 minus, exstans, quasi perforatus videtur; corporeque pellucido nodulis illis 

 linea corporis media, plerumque tamen irregularis oritur. Noduli aperti 

 ovaria sistunt, ovisque ellipticis mediocribus referti sunt, haec etiam saepe 

 circa eosdem effusa sunt. " From these descriptions it is to be seen that while 

 Miiller made correct observations concerning the relations between the 

 positions of the genital openings and the transverse furrows mentioned above, 

 Rudolphi considered the ventral surface to be that on which the openings of 

 the cirrus and vagina are situated and the dorsal that on which the uterus 

 opens to the exterior. 



Van Beneden (1850) seems to have been the first writer to describe the 

 anatomy, vnih however some errors of interpretation as pointed out by Lonn- 

 berg (1891). After Lonnberg's the best and practically the only description 

 of the genitalia was given by Matz (1892:105), Ariola (1900:394) and Luhe 

 (1910:25) obviously copying in part at least from him. 



The earliest traces of the reproductive rudiments appear in toto mounts 

 about 35 to 40mm. from the tip of the scolex. From this region backwards 

 they increase in size, but so slowly that in large strobilas there may be an inter- 

 vening stretch of at least 225mm. before the genital sinus appears. Then 

 the rudiments differentiate very quickly, the first eggs appearing in the uterus- 

 sac about 2mm. farther on in one toto mount made. In the largest strobila 

 at hand the first genital sinuses were seen, when the worm was examined in 

 alcohol, about 375mm. from the tip of the scolex, and the first traces of eggs 

 showed thru the ventral body wall about 20mm. farther on. 



Van Beneden (1850:162) was the first to mention the relations between the 

 external segments and the sets of reproductive organs. He said: "Dans 

 chaque anneau, il y a deux ou trois appareils males et femelles complets; je 

 pense que ces anneaux se divisent encore plus tard, de maniere a n'avoir plus 

 qu' un appareil dans chaque animal," [here "animal" is evidently a misprint 

 for "anneau"]; and further in his footnote referring to the superscript after 

 "complets": "J'ai vu des anneaux qui en contenaient jusqu'a six." In his 

 figure 4, PI. XXI, he showed four parts of the strobila containing evidently 

 three or four sets of reproductive organs in each segment, with the latter sub- 

 dividing so that two sets appeared in each subsegment in the fourth part of 

 the figure. Leidy described the posterior segments of B. scorpii as " ... 

 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." Linton (1890:733) re- 

 ferred to "the phenomenon which the posterior segments present of being 

 welded together in groups of three or four, an appearance which is quite char- 

 acteristic of the posterior segments and which has been alluded to in various 

 descriptions of the species," while further, in connection with the apertures 

 of the reproductive organs: "In the middle of the strobila there sometimes 

 appear to be as many as four or more papillae to a single segment;" and with 

 reference to the specimens from Lophopsetta maculata: "... toward the 



