THE 



MONTHLY MICROSCOPICAL JOURNAL. 



FEBEUAEY 1, 1870. 



I. — On the Stylet-Beg ion of the Ommato]plean Proboscis. 

 By W. C. McIntosh, M.D., F.K.S.E., F.L.S. 



(I?ead hffure fhr PioyaI/ Microscopical Society, Deremhtr S, 1869.) 



(Communicated by Dr. Murie.) 



Plate XXXIX. 



The proboscis, which various authors have burdened with functions 

 so diverse in the economy of these curious worms — as an organ of 

 touch, a penis, and an ahmentary organ, or with bolder fancy have 

 reckoned respectively a parasite and a young Nemertean — fortunately 

 possesses, in the intricacy of its minute structure, sufficient interest 

 to atone for this obscurity of action in the animal system. It forms 

 a long and extremely mobile muscular tube, which has a special 

 opening in front, and is attached by one or more muscular ribbons to 

 the wall of its special sheath, which occupies the median line of the 

 dorsum — quite above the alimentary canal — in all the Nemerteans. 

 On the present occasion the abbreviated description will be confined 

 to the central or proper stylet-region (B, Plate XXXIX.) ; the 

 anterior and posterior regions (A and C) being for the moment 

 overlooked. 



EXPLANATION OF PLATE XXXIX. 



Magnified View (as a traiisi^arent object) of the Stylet-Region of the Proboscis 

 in Oinmatoplea alba. 



a; Anterior region. d, Muscular setting of basal granular 



B, Middle or stylet-region. I sac. 



C, Posterior region. | A, Basal granular sac 

 a, Opening in the floor of the anterior 



chamber. 

 /8, Stylets. 

 S, Fluid vesicle. 

 ^, Duct of stylet-sac. 

 f , C!hamber behind floor. 

 7?, Doubling of the floor of the anterior 



chamber. 



iii, Ejaculatory duct. 



r, Lateral stylet-sac. 



p, Cliamber of the reservoir. 



T, Looping muscles of reservoir. 



7-0, Longitudinal musculiu- layer of 

 reservoir. 



<p. Posterior channel of communica- 

 tion. 



VOL. III. F 



