62 RESEARCHES INT HEIvMINTHOIvOGY AXD PARASITOLOGY. 



tion truncated posteriorly, with parallel margins. Eyes two, reni- 

 form. CEsopliagus simple, cylindrical. 



Length 2 to 3 lines ; breadth 2-5ths to 4-5ths of a line. 



Habitation. — Egg Harbor bay, New Jersey, upon Ulva latissania, 

 Linn. 



Remarks. — Movements same as in the preceding species. When 

 free in water it moves with great rapidity, and rises to the surface 

 in the manner of the leech or the larva of the gnat. 



Gen. NOV. MyzobdelTvA.* 



Body elongated, compressed fusiform, smooth. Head continu- 

 ous with the bod}', subindibuliform, obliquely ventrally terminal. 

 Mouth central, unarmed. Acetabulum ventrally obliquely terminal, 

 concave, not corneous. 



7. Mvwbdella Lugiibris, n. s. 



Body cylindro-fusiform, in transverse section, elliptical, black 

 olivaceous green, anteriorly narrowed, cylindroid ; posteriorly in- 

 crassate. F'rom 15 to 18 annulations. Integument translucent, 

 permitting the sacculated intestine of a black green hue to be visible. 

 Acetabulum circular, concave, a little larger than the oral disk. 



When elongated 10 lines, by ^ line in breadth posteriorly, i-5thof 

 a line anteriorly. Will contract to 4 lines by 4-5ths line in breadth. 



Habitation. — Parasitic upon the common edible cr3.h,Li/pa dica?if/ia, 

 M. Edw. ; usually found attached about the base of the limbs. 



Meckelia, Lhuckart. 



8. Meckelia Ladca, n. s. 



Body very soft, milk white, in transverse section lenticular, con- 

 vex above and below ; when extended, very much compressed, more 

 especialh' posteriori}', incrassate rounded just posterior to the head ; 

 lateral margins thin, undulating ; posterior extremity thin, sub- 

 acute. Head compressed, conical or hastate, anteriorl}^ obtuse, 

 breadth at base i line; lateral cleft i "^ lines long. Generative 

 aperture longitudinally oval. 



Greatest length 6 inches : ordinarily 5 inches, by 3 lines in breadth, 

 and I line in thickness : may contract to i inch in length, by 2 lines 

 in breadth, and i '^ lines in thickness. 



Habitation. — In mud and sand under stones, dead shells, etc., in 

 positions uncovered at low tide, upon the coast of Great Egg Harbor, 

 New Jersey. 



*Myzobdella : — //.'->^w, I suck ; /Sfk/za, a leech. 



