178 TAPEWORMS OF HA E ES A XD E A B BTTSS TILES. VOL. xix. 



Riehm 1 in 1881 studied the tapeworms of rabbits and hares, and in 

 a preliminary account of his work described this same form as Citto- 

 tcenia latissima, new genus, new species. Later 2 he placed this species 

 in the genus Dipylidium with the following specific diagnosis : 



Kopf hakenlos liber f min. breit, rnit stark vorspringendeu Saugnapfen und 

 da<lurch gegen die lanzettformig sich verbreitermlo Gliederkette deutlich abgesetzt. 

 Geschlechtsciffnungen beiderseits, in den zitzenartig vorspringenden Hinterecken 

 er Glieder, welche den Riindern, besonders der contraliierten Thicre ein gefranztes 

 Ansehen verleihen. Glieder stets viel kiirzer als breit und uamontlich nach den 

 Seiten bin ungemein dick. Liinge im gestreckten Zustaude bis 80 cm., Breite der 

 reifsten Glieder 15 mm. und dariiber Wobnthier: Lepus cuniculus. 



Of anatomical details he gives the following, which appear to me to 

 be of importance: 



Segments may attain 3 to 3.5 mm. in thickness; the strobila is generally found in 

 the lower portion of tbe small intestines and is of a grayisb to a reddish gray 

 in color, something like Lothrioceplialtis latns. Black pigment on the suckers and 

 genital pores. Suckers prominent; neck short. Genital anlagen appear very early. 

 Male organs: Testicles very numerous, 0.115 mm. in diameter, scattered throughout 

 dorsal portion of median field; cirrus pouch large, provided with three layers of 

 mucles, two circular and one longitudinal layer, cirrus is generally protruded. 

 Female organs : Vagina opens close to cirrus, and is quite thin; median to the longi- 

 tudinal canals it swells into a receptaculum seuiinis; female glands essentially the 

 same as in Dipylidium pectinalitm, but situated very close to the longitudinal canals. 

 The uterus is described "'not as a simple tube, widened here and there, and running 

 transversely through the segment, but it is broken up into two or three such tubes, 

 which unite here and there, and thus cut the parenchyma up into islands. This 

 structure is seen, however, only in segments without eggs. Through the pressure of 

 the developing ova these tubes widm so that the islands of parenchyma are sup- 

 pressed and the uterus then appears as a single tube." In some segments an extra 

 (third) set of female glands was observed right or left of the median line. Excre- 

 tory system very highly developed; in the younger segments it is composed of a net- 

 work of canals, with one lateral canal which is especially large; transverse canal 

 with numerous anastomoses present; as the genital organs develop, the canals of the 

 median field become more or less suppressed, but three or four lateral canals persist 

 each side and the transverse canals at the posterior margin become larger, so that 

 the excretory system now bears more of a resemblance to that of JJipylidium pectina- 

 tum; the second canal system (dorsal canal) resembles that of Dipylidium leiickarti. 

 (Abstract.) 



Neumann 3 in 1888, places this worm in the genus Tcenia. 



Blanchard 4 m 1891 examined Baird's specimens and recognized them 

 as identical with D. latissimiim, Eiehm. He also examined fresh speci- 

 mens, which he describes in some detail. 



Strobila measures 40 to 50 cm. long and contains about 210 segments ; bead, 0.8 mm. 

 broad by 0.63 long. Neck absent, segments may attain 4 mm. in length by 15 in 

 breadth. Genital pore appears about the seventy-eighth segment; in the older seg- 

 mnets it is more distal than in the younger segments ; egg is spherical 52 to 60 //; 

 bulb of pyriform body 16 to 24 //, horns long and curved. (Abstract.) 



1 [Untersuchungen an den Bandwiirmern der Hasen und Kaninchen, Zeitschr. ges. 

 Naturw. 3 ser., VI, 1881, p. 200. 



2 Studieu an Cestodeu, Zeitschr. ges. Xaturw., 3 ser., VI, 1881, pp. 583-590. 



3 Trait6 des maladies parasitaires, p. 426, Paris, 1888. 



4 Me"m. Soc. zool. France, IV, 1891, pp. 444, 451, 452-457, figs. 21-25. 



