Messrs. Hancock and Embleton on the Anatomy o/Eolis. 81 



d^une substance granuleuse bien moins transparente que le reste 

 des tissus. II m^a semble reconnaitre en outre Fexistence de tres 

 petits orifices s^ouvrant dans Finterieur du caecum/^ Now in the 

 numerous species we have examined, we have seen nothing to war- 

 rant the idea here laid down. From our statement above it will be 

 seen, first, that we believe these prolongations of the branches 

 of the digestive cavity not to be cseca, and secondly, that they are 

 not simple tubes having a granular substance coating them, but we 

 find that the walls of the tubes are more or less bulged or thrust 

 outwards into the form of simple or compound follicles, and that 

 the walls are lined throughout by the granular matter we have 

 already described; in fact, that each papilla contains a perfect 

 gland of distinctly follicular type. PI. IV. fig. 5. shows a lon- 

 gitudinal, and PL IV. fig. 7. a cross section of a papilla of E. pa- 

 pulosa ; a in each represents the great central channel from which 

 on all sides branch ofi" large canals that end in small imperforate 

 diverticula. 



The whole internal surface of this compound gland is furnished 

 with minute vibratile cilia, as likewise the small canal that leads 

 to the oval vesicle ; the cilia do not appear to be continued into 

 the vesicle. We have however seen, on examining these parts 

 under pressure, small granules which had accidentally passed 

 into the tube, driven by the ciliary motion into the vesicle. 



Having described the glandular apparatus, we now pass on to the 

 vesicle at the extremity of the papilla. This vesicle is of an ovoid 

 form ; its long diameter in the largest specimens measures about 

 2^ gths of an inch, its narrow end lying within the very apex of 

 the papilla ; both ends are perforated ; the narrow end opens ex- 

 ternally through a round aperture in the skin covering the apex 

 of the papilla, the opposite extremity communicates with the 

 gland by means of the slender tube, of variable length, which 

 has already been noticed. 



The walls of the vesicle, which are seen of an opake white in 

 those species which have transparent skin, is fused with the inte- 

 gument of the papilla round the external orifice ; and below this 

 stout muscular bands, PL IV. fig. 9 e, attach the vesicle to the 

 skin, so that during the contractions of the papilla the vesicle is 

 held secure in its position. In E. papillosa the wall of the vesicle, 

 PL V. fig. 12, consists throughout of a strong thick layer of finely 

 interwoven circular muscular fibres. The contents appear to be 

 arranged in longitudinal masses, as represented in the longitu- 

 dinal section, PL V. fig. 1, which in a cross section, PL IV. fig. 8, 

 have a triangular outline, the apices not quite reaching the axis 

 of the vesicle. There is therefore a free space corresponding to 

 the long axis. If we take out a portion of the contents of the 

 vesicle and place it under the ^th-inch object-glass of the micro- 



