PROCEEDINGS OF THE XJTIOXJL MUSE CM. 189 



about ]0 mm. broad by 1.5 mm. long. The aulageii of the genital organs 

 appear very early; the female aulagen are found near the longitudinal 

 canals immediately back of the head; testicles appear about mm. 

 back of the head; genital pores double, in ])()Sterior half of margin. 

 Male organs: Tlie testicles are about 0.04 mm. in diameter; they are 

 numerous, about 150 in number, contined to distal half of segment, 

 posterior to uterus, and extend across the entire median held passing 

 tlie ovary on e;ich side to the longitudinal canals; cirrus pouch unusu- 

 ally large, attaining 1 mm. in length, extending some distance median 

 of the longitudinal canals. Female organs: Ovary, shell gland, and 

 vitellogene gland situated some distance median of the ventral canal, 

 about 1 mm. or more from the lateral margin; a common transverse 

 uterus to both ovaries; it passes the ovary veutrally, is generally larger 

 in its lateral portions than in its median portion, ami increases its 

 volume byi)roxinial and distal branches. Excretory system: Dorsal 

 canal not observed; ventral canal median of nerve; transverse canals 

 connected by secondary longitudinal canals. Longitudinal nerves close 

 to lateral margin. Cirrus pouch, vagina, and uterus pass from median 

 tiehl into lateral field dorsally of nerve and longitudinal canals. Cirrus 

 l)ouch dorsal of vagina on both sides of the segment. Ova globular 50 to 

 84 // in diameter; bulb of pyriform body 14 to 10 //; horns long, curved. 



Hosts. — Common European hare {Leuns timidus) by Goeze, K'ielim. 

 von Linstow, and Stiles; Mountain hare {L. variabilis) by E. Blanch- 

 ard. Development unknown. 



Types. — Original types?. Cotypes of Eiehm in the collection of 

 Leuckart; No. 1411, U.S.N.M. Typical specimens in collection of 

 Blanchard; collection of Moniez; collection of Stiles (Xos. 110, 1:234, 

 1238, U.S.N.M.). 



Geographical distribntio)i. — Europe: Germany (Saxony by Kiehm and 

 Stiles; ? by Goeze); France (Biianron by li. Blanchard; ? Lille by 

 Moniez). 



CITTOT^NIA PERPLEXA (Stiles, 1895), Stiles & Hassall, 1896. 

 (Plate XVIII, figs. 1-3.) 



1895, Ctenotwma perplexa, Stiles, Veterinary Magazine, II, June, p. 345. Aug. 28, 1896. 



1896, CitLotduia 2)erplexa (Stiles, 1895), Stiles & Hassall, Veterinary Magazine, III, 



p. 407. 



The specific name perplc.ra was proposed because it was so difficult 

 to decide what to do with the form under discussion. Some half a 

 dozen specimens were collected by Hassall from Lepus sylvativus in 

 Bowie, Maryland. They are all contracted and measure up to 57 mm. 

 long by 10 mm. broad. 



The parasite resembles C. pectinata in general form in the early 

 appearance of the genital aulagen and in the fact tliat the testicles 

 extend beyond the ovaries to the lateral canals. It differs from C. pec- 

 tinata- radically in the size of its cirrus pouch and vagina, and in the 



