RESEARCHES IN HELMINTHOLOGY AND PARASITOLOGY. 6 1 



Pr^ANARIA, MtJLLER. 

 SUB-GKNUS NOV. BdELIvOURA.* 



Characters same as Planaria, without tentaculse, and the posterior 

 extremity of the body separated by a constriction .serving as a disk 

 of attachment. 



5. BdcUoura Parasitica, n. s. 



Body milk white, with a faintly yellowish intestine showing through 

 the translucent integument, smooth, thin, lanceolate, or spatulate ; 

 anteriorly narrowed, obtu.se ; lateral margins, thin, undulating ; con- 

 stricted portion posteriorly truncated, nearly as broad as the middle 

 of the body. Eyes two, reniform. CEsophagus, .simple, cylindrical, 

 campanulate when protruded. 



Eength from 3 to 10 lines; breadth 2-5ths to 2I4 hues. The 

 longest may contract to 6 lines by 3}^ lines. 



Habitation. — Parasitic upon the King Crab, Polyphemus occidentalism 

 Lam. Found often in great numbers, adhering with considerable 

 tenacity by means of the posterior constricted extremity of the body 

 to the under surface of the branchial covers, the branchial laminae, 

 and to the extremities, especially in the vicinity of the joints. 



Remarks. — When the King crab is removed from the water its 

 planaroid parasite retires to the deepest recesses between the limbs 

 and other external organs to avoid evaporation. The parasite moves 

 with a gliding motion, like the species of Planaria, and also by fixing 

 the posterior extremity and extending the anterior part of the body 

 to its greatest length, and then abruptly detaching and drawing 

 forward the former, like the leeches. At other times it fixes itself 

 posteriorly, and waves the anterior portion of the bod}' to and fro 

 through the water. 



Attached to the branchial laminae of the King crab are frequently 

 ob-served ochreous or brownish, oval, compressed cysts, from \l to 2 

 lines long and i-6th to i line broad, attached by a short pedicle at 

 one extremity, and unusually closely applied to the surfaces between 

 the branchial laminae, which are receptacles or ova ? of the Bdelloura 

 parasitica. Occasionally the margin of the cysts is improved with a 

 fringe of short irregular, blackish filaments. Sometimes these cy.sts 

 exist in such numbers as to have the appearance of flaxseed sprinkled 

 between the branchial laminae. 



6. Bdelloura Rustica, n. s. 



Body brownish or blackish, translucent, lanceolate ; anteriorly 

 narrowed, obtuse, lateral margins thin, undulating ; constricted por- 



* />'«£//«, a leech ; tail ; because the animal adheres by the tail like a leech. 



