OBSERVATIONS ON LIVING SOLENOMYA. 



269 



point in the general direction of the median line, but are disposed 

 irregularly in the membrane, some inclined forward and others 

 backward, but most of them are at right angles to the mantle 

 border (Fig. I, G). Under a higher power these bodies have the 

 appearance of setigerous follicles. Stempell figures one in his 

 memoir of 5. togata as a simple alveolar border gland. His 

 figure shows a much more bulbous gland and the thread-like 

 extension is not shown as in those here figured (Fig. 5). It was 

 some time before I determined that there was no protuberance 

 beyond the surface of the mantle, so strong was their resemblance 

 to setigerous follicles. 



FIG. 7. FIG. 8. 



FIG. 7. Anterior view of animal. 



FIG. 8. Anterior end from below: A, anterior adductor muscle; F, foot in sec- 

 tion; H, hepatic follicles; M, mouth; P, palp-appendages; R, pedal retractors. 



The margin of the mantle becomes thickened as it borders the 

 anterior end of the shell and ends abruptly just before the shells 

 meet dorsally. Just in front of where the shells meet above are 

 two short unpaired tentacles or tubercles in the median line and 

 then ten or more on the edge of the rounded anterior edge of 

 the mantle on each side diminishing in size, however, toward 

 the ventral region, where they cease (Fig. 7). Writers have 

 described the whole free edge of the mantle as bearing these 

 papillee and even shown them in figures. Looking at this region 

 from below the abrupt termination of the thickened mantle 

 margin and the papillae are shown (Fig. 8). A triangular mus- 

 cular layer seems to connect the two thickened portions of the 

 mantle dorsally. Also a narrow band of fibers runs from the 



