1 886.] NEW- YORK MICROSCOPICAL SOCIETY. 71, 



have worked out under the scales to the exterior, can, under a 

 one-sixteenth or one-twentieth inch objective, be seen like little 

 dots, as shown at E, Figs. I. and II. I have seen a pigment cell 

 about half way out, which, in a few days, under my observation, 

 worked its way entirely out. 



I believe that the trail left by certain animals is caused by the 

 rubbing off of some of these pigment cells, which I think contain 

 some material which dogs can smell. Animals which leave the 

 strongest trail always have dark hairs on the feet. The deer 

 probably discharges some form of pigment cell from his hoof. 



EXPLANATION OF PLATE III. 



Fig. I., Exterior view : E, Pigment cells on exterior of fibre 

 from the Common Kabbit. 



Fig. II., Interior view : A, Air cell ; B, Compacted pigment 

 cells ; C, Wall of fibre ; D, Loosened pigment cells. 



Fig. III., Whole fibre: G, No scales; H, Prominent scales ; 

 /, Scales as in Fig I.; /, Scales gradually lessening toward 

 point of fibre. 



SPIRAL FIBRE OF THE BANANA STALK. 



BY THE REV. J. L. ZABRISKIE. 



{Read April 2d, 1886.) 



The spiral fibres of the large stalk which supports the fruit- 

 bunch of the Banana are remarkable for their abundance, large 

 size, and beauty. If a prism be cut longitudinally from the 

 inner substance of the stalk, one-quarter of an inch square and 

 of any convenient length, and slight transverse incisions, all in 

 the same plane, be made on the four sides, on slight bendings 

 in various directions, the cells and vessels which have not been 

 cut will break, and the portions of the prism on either side of 

 the incisions may be gently separated, drawing out the spiral 

 fibres in great abundance. These fibres tear away from their 

 respective vessels in ribbons which vary greatly in fineness, as 

 may be easily detected by the unaided eye. The appearance of 

 ribbons is caused by parallel strands of the fibres, from three to 

 thirteen in number, coming away together from their vessels, 

 and adhering, until they are drawn for a considerable length. 

 Many of them may be drawn out at least two inches before they 

 break. In order to observe the beauty of the large ribbons, it 



