558 PROCEEDINGS OP THE AMERICAN ACADEMY. 



of finely granular substance, which in the papilla appears to surround a 

 narrow cavity, and there is connected with this sheet a thick layer of 

 fibrous tissue." 



Connective-tissue fibres pass from the connective tissue of the pro- 

 boscis into the papillae (PL 1, Fig. 4; PL 2, Fig. 11 ; PL 3, Figs. 12, 

 19, 20 ; PL 4, Fig. 27) ; as a rule, these could not be traced more than 

 half-way to the apex of the papilla, but sometimes the contents of the 

 papilla, in great part or entirely, looked fibrous (PL 1, Fig. 4 ; PL 3, 

 Figs. 12, 15, 19). These fibres of the papilla are, as Ehlers says, in 

 close connection with a finely granular substance. There is a particu- 

 larly dense and deeply stained layer of this finely granular substance 

 immediately under the cuticula (PL 1, Figs. 3, 4; PL 2, Fig. 11 ; PL 3, 

 Fig. 16; PL 4, Fig. 30) ; it surrounds not a cavity, but a central re- 

 gion in which there is a little granular substance and in which there 

 are many vacuoles. At one point of the base of the papilla, where the 

 connective tissue enters (PL 1, Fig. 4; PL 2, Fig. 11), and again at one 

 point near the apex, apparently in the region of the sensory termination 

 of the papilla (PL 4, Fig. 30c), there is a break in the dense layer of 

 finely granular substance. 



Of the two basal nuclei (nl. ba.) one is near the anterior, the other 

 near the posterior face of the papilla (PL 2, Fig. 96). They are sphe- 

 roidal or ellipsoidal, and contain small irregularly scattered chromatin 

 granules in large numbers ; but in preparations stained in haematoxylin 

 (PL 1, Fig. 3; PL 2, Figs. 9/>, 11 ; PL 3, Figs. 16, 17) they appear less 

 deeply colored than the remaining nuclei. 



The more distal nuclei (nl. ax.) are more elongated, being ellipsoidal 

 or spindle-shaped. They present an elliptical outline whether seen in 

 sections perpendicular to the axis of the proboscis (PL 1, Pigs. 3, 4 ; 

 PL 2, Fig. 11 ; PL 4, Fig. 30c), in longitudinal sections of the pro- 

 boscis passing through the axis of the papilla (Fig. 28), or in sections 

 perpendicular to the axis of the papilla (PL 2, Fig. 9a; PL 3, Figs. 16, 

 '17). The outline may be more or less pointed at one end, and is more 

 nearly circular in the sections perpendicular to the axis of the papilla 

 than in those parallel to the axis. The deeply staining granulations of 

 the distal, or axial, nuclei are larger and not less numerous than those of 

 the basal nuclei ; and it is perhaps for this reason that the first-named 

 nuclei appear more deeply stained than the basal ones. The gran- 

 ulations of the axial nuclei are also more evenly distributed. Both 

 kinds of nuclei have a clearly defined nuclear membrane. In the prep- 

 arations fixed in sublimate-acetic and stained in Kleinenberg's haema- 



