RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 37 



annuliis long, constricted in the middle. Tail nearly one-third the 

 length of the body, shining, straight or curved. Pharynx short. 

 CEsophagus consisting of two elongated, pyriform, muscular bulbs. 

 Neck of first oesophageal bulb dilated at commencement and middle; 

 neck of second long, narrow, and cylindrical. Ventriculus largely 

 dilated and oval at commencement, afterwards cylindrical. 



Length of body i line ; breadth opposite ventricular dilatation 

 I -136th inch; just above anus i -300th inch ; greatest do. i- 107th 

 inch ; length of tail i-4oth inch ; breadth at middle i-i 360th inch ; 

 length of first pyriform bulb of oesophagus i- 150th inch ; breadth 

 of neck do. i-iiooth inch ; do. of body of do. r-40oth inch ; length 

 of second bulb i-2i4th inch ; breadth of neck i-i30oth inch ; do. of 

 body I -340th inch ; do. of dilated commencement of ventriculus 

 i-2i4th inch ; do. of cylindrical portion i-33oth inch. 



Ova oval, i-3ooth inch long by i-625th inch broad. 



Habitation. — Found in numbers of one to half a dozen in the small 

 intestine of our domestic cockroach {Blatta oricntalis). This species 

 was discovered by Hammerschmidt, who named it Oxyiiris diesingii, 

 but as it is considered a doubtful compliment to name intestinal 

 worms after persons, in placing it in the genus Streptostoma, I have 

 also changed the specific name. The individuals from which my 

 description is taken were the largest I found. 



Sub-genus Thelastoma. Proc. Acad. Nat. Sci., 1S49, p. 231. 



2. Thelastoma appendiculatum. — Body c^dindrical, narrowed ante- 

 riorly and posteriorly, white, translucent, shining, strongly annu- 

 lated. First division of the oesophagus moderately long, cylindrical ; 

 second portion short, broad, and pyriform, ventriculus dilated cordi- 

 form at commencement, becoming rapidly narrowed and c}dindrical, 

 and sending off posteriorly a large and long p^^riform diverticulum 

 orcoecum, afterward cylindrical to termination, and forming a single 

 short convolution just posterior to the generative aperture. Tail 

 straight, spiculate, one-fourth the length of the body. Eighty-five 

 annulations to the body, of which there are twenty-eight from the 

 mouth to the commencement of the ventriculus. Generative aper- 

 ture twenty-six annulations from the anal aperture. Last annula- 

 tion furnished with two short spines projecting backward. 



Length of body i line to i-iothof an inch ; breadth at ventricular 

 commencement i-iooth inch, at middle i-8oth inch, at anus i-i6oth 

 inch; tail i-5oth inch long, breadth at middle i -888th inch ; first 

 portion of oesophagus i-8oth inch long, i-533d inch broad ; second 

 portion i -240th inch long ; neck of do. i -666th inch broad, body of 

 do. I -250th inch ; commencement of ventriculus i-200th inch broad ; 



