72 RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 



Catesthia,* Genus novcm. 



Body very soft, cylindroid. Head continuous with the body. 

 Moutli infero-terminal; oesophagus amphoraform. Eyes two, deeply 

 seated in the interior of an oval translucent space of the integument. 



I. CatcstJna Stellato-Maculata, Leidy. 



Body long, cylindroidal ; anteriorly and posteriorly obtusely 

 rounded ; superiorly maculated closely and regularly with very 

 much branching, stellate, black pigment cells, which cease abruptly 

 latterly, and anteriorly form 3 lobes, in the translucent whitish in- 

 terspaces of which, deeply seated, are the eyes, which are black and 

 globular ; inferiorly translucent whitish. Mouth round, very large 

 and dilatable ; oesophagus amphoraform, very large. 



Length 3 to 8 lines, breadth i-4th to i line; thickness i-.sth to 

 4-5ths line. 



Habitation. — Upon the under side of stones in the Delaware and 

 Schuylkill rivers, below tide-water mark. 



Remarks. — Closel}^ allied to Vertex, Hemp, and Ehrenb., but has 

 not four eyes, and has a differentl)^ arranged generative apparatus. 



It is exceedingly voracious. I have seen an individual of 8 lines 

 in length swallow whole a Planaria viacu/ata 6 lines in length. 



[December, 1851. No 98. See Bibliography.] 



CONTRIBUTIONS TO HELMINTHOLOGY. 



MiCROSTOMUM? OKRSTED. (EuSTOMUM.) 



Body elongated, compressed, cylindroid, vibrillated. increasing 

 by transverse segmentation in pairs. Head continuous w^th the 

 body, furnished upon each side with a respiratory fovea. Mouth 

 antero-inferior ; intestinal canal produced anterior to the mouth in 

 the form of a coecum ; oesophagus amphoraform, muscular, not pro- 

 tractile ; anus at first (after segmentation ) open, afterwards becom- 

 ing closed. Ocelli none. Minute rhabdocaela inhabiting fresh 

 water. 



This genus is the Microstomum of Oersted, if what I have ob- 

 served to be lateral respiratory foveae of the head are, according to 

 him and other authors, ocelli destitute of pigment. 



In numerous individuals of what I have considered below to be 

 of three distinct species of the genus they were always observed to 

 be in a state of division by pairs, and the primary pair of segments 



* Catesthia : Ko-ktOud. devour. 



