46 A FAUNA WITHIN ANIMALS. II. 



Habitation. — Found within the large intestine of Julus marginatus, and less fre- 

 quently within the ventriculus. 



3. iStreptostomum g^racile, Leidt. 



Proo. Acad. Nat. Sci., v., 100 ; ib. v., 285. 



Syn. Oxyuris Diesingii, Hammerschmidt: Isis, 1838, 354, Taf. iv., Fig. 6. 



Oxyuris Blattce Orientalis, Hammerschmidt: Naturwissenschaftliche Abhandlungen von Haid- 



iNGER, I. 284, Taf. X., Figs. 4, 7, 13-15. 

 Anguillula macrura, Diesing : Systema Helminthum, II. 134. 



(Plate VII. Figs. 6, 7.) 



Female. — Body cylindroid, attenuated from the middle anteriorly and posteriorly. 

 Anterior annuli very long and movable upon one another ; posterior annuli shorter 

 and not so distinct. Oral annulus short, simple ; second annulus long, constricted in 

 the middle. Tail nearly one-third the length of the body, straight or curved, spi- 

 culate, shining. Mouth round, simple ; buccal organ elongated pyriform, with the 

 neck cylindroid, dilated at its commencement and middle, extending through ten 

 annuli ; gizzard with a narrow cylindroid neck and globular body, extending to the 

 eighteenth annulus; intestine cylindroid, very largely dilated oval at commence- 

 ment. 



Measurements. — Length of body 1 line ; breadth opposite the ventricular dilata- 

 tion y|^-g- inch ; greatest do. y^y inch; just above anus -^^-q inch. Tail ^jij- inch 

 long by the y 3V-0 iiich broad at middle. Buccal organ j^^ inch long ; gizzard ^\-^ 

 inch long. Ovum oval, g^^- inch long, g^-g- inch broad. 



Habitation. — Pound within the intestinal canal of Blatta orientalis. 



§ 5. Description of the Genus and Species of Thelastomum. 



TeELASTOMrm, Leidt. 

 Body cylindroid, annuli moderately long. Oral annulus papillaeform. Mouth 

 small, circular, without lobes or other appendages ; buccal organ long, cylindrical ; 

 gizzard pyriform. Tail moderately long, spiculate. Penis consisting of a single 

 spiculum. 



1. Thelastomum attenuatum, Leidy. 



Proc. Acad. Nat. Sci., iv., 231 ; ib. v., 285. 



(Plate VI. Fig. 4; VII. 1, 23. 



Female. — Body cylindroid, translucent white, shining, attenuated anteriorly from 

 the commencement of the intestine, divided into from 140 to 160 annulations. 

 Oral annulus minute, papillaeform ; second annulus small, compressed oval. Tail 

 very straight, or slightly curved, slender, spiculate, acute. Mouth small, simple ; 

 its passage extending through two and a half annuli ; buccal organ and gizzard 

 extending through 55 annulations, the former, very long, cylindrical, rounded at 



