186 TAPEWORMS OF HARES AND RABBITS— STILES. volxix. 



is too indeliiute to alloM' a specific or even generic detcriiiiiiation. lu 

 1803 lie transferred tlie species to Halijuin. 



Rudolplii ' in 1810, as Riebni remarks, certainly liad more than Gueze's 

 species in mind when lie wrote his diagnosis; a i>ortion of liis descri]>- 

 tiou applies very well to C. denticulate, and a portion to C. ctcnoides. 

 He includes Zeder's single-jiored form in T. pccthuttn. The fragment of 

 liudolphi's (1810) specimen of T. pcctinata which 1 examined is so 

 poorly ]>reserved that no statements can be made on it, but. as Stiles 

 and Hassall in 1896 have shown, part of Kudolphi's original material 

 of T. deniiculata belongs to this species. 



Bremser - in 1824 gives two ligures of T. pect'nutta, in regard to which 

 Riehm remarks that Figure o is an unquestionable J), leacl-arti, while 

 Figure G (head) is similar to 1). latiHs'imum {=C. dcntk-ulatn). 



Diesing's^ description of 1850 can be made to apply to several dif 

 ferent forms; he includes all the literature given for T. pevthmtu. 



Our chief knowledge of C. pectinata we owe to Eiehm in ISSl, who 

 studied its anatomy in detail. Eiehm divided the heterogeneous mass 

 of tapeworms, which earlier authors had included under the term 

 T. peetinatd, into Ave species, which he named T. rhopidoccplKdn and 

 T. rhopaUocephnla (single-pored forms), and Dipylidiiun pectinatnm, D. 

 leuclarti, and J>. Jatissi)in(iii (double-pored forms). This is the first 

 time, therefore, that T. 2)ectin((t(( yvas described in detail, so that this 

 species stands to-day npon Riehm's division, he having designated the 

 particular parasite which should bear Goeze's specific name. 



liiehm^ diagnoses his form as follows: 



Kopf bakenlos, ansserordentlicli kleiii, k;inm } unii. breit, gegen die JanzetttV'ir- 

 niig sich verbreiterndo Strobila uicbt abgesetzt. Geschleobtsuff'uuiigeu beMer-eits, 

 fast iu der Mitte des Proglottidenrandes. Glieder kurz, trapezformig, auch iiu 

 gestrecktesteu Zustande miudestens 4 lual breiter als lang. Liiuge ('.es aus«estroc-k- 

 teii Wurnies nicbt iil)cr 40 cm. meist geriuger. Breite der reifstcu Proglottiden bis 

 8 mm. Die Strobila ist oftdurch Liingsfalten gestreift. Wohutbier: Lepiis iimidiis. 



This diagnosis is hardly detailed enough to meet the re(juireiiients of 

 the present day, but in the anatomical <leseriptioii Kiehm gives data 

 wliich supply what is lacking in the passage just (pioted. ^lany of the 

 points he mentions can hardly be looked upon as specific characters, 

 but should, I believe, be attributed to influences of technique, individ- 

 ual A'ariation, and jwssibly the specific influences of environment, 

 namely, the host — a subject to which the lu'liiiinthology of the future 

 must certainly give its most serious and careful (consideration. T::e 

 characters which appeal to me most in Riehnrs des('ii[)tiou may be 

 briefly summarized as follows: 



Male organs: Tbe testicles jorm a continuous baud across the median field iu the 

 distal portion of the segment, and in Plate VI, lig. 4, thej' extend laterally close to the 



'Entozooruui sive Vermium intestinalium Historia naturalis, II, Ft. 2, Amstelse- 

 dami, pp. 8l'-8l. 



^Icoues Helmintiuun, jd. \iv, ligs. 5-6. 

 "Systema Helniintbum. I, 1850, p. 498. 

 ■•Loc. cit., p. 575. 



