ON A LITTLE-KNOWN SENSE-ORGAN IN SALPA. 97 



EXPLANATION OF PLATE X, 



Illustrating Mr. Arthur Bolles Lee's paper " On a Little- 

 known Sense-organ in Salpa." 



Fig. 1. — Anterior half of a Salpa mucronata. tu. The tunicia mantle. 

 g. The ganglion, ci. The ciliated fossa. mo. "Mouth" of the mantle. 

 5. 0., s. 0. The two sense-organs. X 20. 



Fig. 2. — A sense-organ in the living state, cl. The outer contour of the 

 claviform appendage, un. The annular depression, v. The vestibule of the 

 bulb, in which the terminal arborescence of the nerve is well seen. Optical 

 section, x 1100. 



Fig. 3. — A sense-organ after preparation (solution of Flemming, Henneguy's 

 acetic-acid alum carmine, damar). cl. The outer contour of the claviform 

 appendage. I. Its lumen. I. ca. Lip of the calyx, int. ca. Internal cells of 

 the calyx. e,vt. ca. External cells of the calyx, gr. Granular mass in which 

 the sense-cells are embedded, t. s, h. Termination of sense-hairs, an. Annular 

 depression of the tunicin mantle, v. Vestibule of the bulb. Optical section. 

 X 1000. 



Fig. 4. — A similar preparation without the claviform appendage. The 

 letters as before. Optical section, x 1600. 



Fig. 5. — A similar preparation seen in optical transverse section, ca. The 

 cells of the calyx, s. c. The sense-cells, the letters pointing to a fourteenth 

 cell, which is indistinctly seen, x 1100. 



VOL. XXXII. PART. I. — NEW SER. 



