48 A FAUNA WITHIN ANIMALS. H. 



Habitation. Found within the ventriculus and large intestine of Polydesmus 

 virginiensis. 



4. Thelastomum robustnm, LEIDY. 



Proc. Acad. Nat. Sci., v., 101 ; ib. 285. 



Female. Body white, cylindrical, narrowed anteriorly and posteriorly, divided 

 into from 200 to 220 annulations. Oral annulus simple. Tail straight, little more 

 than one-eighth the length of the body. Mouth round, simple ; buccal organ and 

 gizzard extending through forty annulations ; intestine largely dilated oval at 

 commencement. Generative aperture 70 annulations anterior to the anal. 



Measurements. Length of body 2 lines ; breadth at the commencement of the 

 intestine ^ of an inch ; at middle fa of an inch ; just above the anus -fa of an 

 inch. Length of tail -fa of an inch ; breadth at middle ifa-^ f an inch. Buccal 

 organ -fa of an inch long ; gizzard T | r of an inch. Ovum -gfa of an inch long by 

 -^g- of an inch broad. 



Habitation. Intestinal canal of the larva of a lamellicorn coleopterous insect. 



7. Thelastomum brevicaiidatiim, LEIDY. 



Proc. Acad. Nat. Sci., v. ( 208 ; ib. 285. 



Female. Body cylindroid, anteriorly rapidly narrowing from the commencement 

 of the intestine, posteriorly abruptly rounded ; with a very short spiculate tail. 



Measurements. Length of body to 2 lines ; breadth at commencement of intes- 

 tine -fa of an inch; at middle -fa of an inch; just above anus T |^ of an inch. 

 Length of tail from anus ^ u of an inch. Buccal organ fa of an inch long ; gizzard 

 ^fj- of an inch long. Ovum oval, -^fa of an inch long. 



Habitation. Intestine of the larva of Scarabasus relictus. 



6. Thelastomuin gracile, LEIDY. 



Proc. Acad. Nat. Sci., Y., 285. 



Oxyuris gracilis, Hammerschmidt : Isis, 1838, 353, Tab. IV. c-f ; Naturwis. Abhandl. v. HAID. I. 287, Tab. 



X. Figs. 21-25. 

 Anguillula gracilis, Closing: Syst. Helm. II. 133. 



7. Thelastomum depressum, LEIDY. 



Oxyuris depressa, Hammerschmidt: Isis, 1838, 354, Tab. IV. d. e. 



Oxyuris dilatata, Hammerschmidt: Naturwis. Abhandl. v. HAID. I. 287, Tab. X. Figs. 26, 27. 



Thelasloma dilatation, Leidy: Proc. Acad. Nat. Sci., v., 285. 



Anguillula depressa, Diesing: Syst. Helm. II. 133. 



8. Thelastomum laticolle, LEIDY. 



Proc. Acad. Nat. Sci., v., 285. 



Oxyuris laticollis, Hammerschmidt: Naturwis. Abhandl. v. HAID. I. 288, Tab. X. Figs. 28-34. 

 Anguillula laticollit, Diesing: Syst. Helm. II. 134. 



