1912.] NATURAL SCIENCES OF PHILADELPHIA. 427 



homologous with the most marginal row of the distal suckers; proxi- 

 mal to the hooks and in a line with them on the right tentacle club 

 is usually situated a single minute sucker similar to those just de- 

 scribed. Certain variations occur, as (e.g.) in the club from which 

 the accompanying figure (PL IX, fig. 6) was drawn; here the small 

 suckers opposite the hooks were apparently wanting (through abra- 

 sion ?) and were supplied in the drawing from another specimen. The 

 general character and extent of these variations are well brought 

 out in the accompanying table of data taken from all the specimens 

 examined and would seem to indicate that where the number of 

 minute suckers is fewer than that above regarded as typical, it may 

 be due to the facility with which such delicate structures may be 

 lost by abrasion. 



Fixing apparatus well developed and with one exception very 

 constant in comprising four minute suckers and four pads regularly 

 alternating in two rows; sometimes these are relatively distant as 

 in the figure, but often more compactly grouped. The distal (sucker- 

 bearing) part of the club is furnished with a membranous keel along 

 its dorsal margin (PL IX, fig. 6). 



Buccal membrane eight-pointed, papillose within; its color deep 

 violet, the supporting lappets of a conspicuously paler shade out- 

 wardly. 



Gladius (fig. 3) with broad wings, embracing the slender midrib for 

 quite three-quarters of its length ; only slightly subangulate laterally 

 at the point of widest expansion. Keel plainly visible through the 

 dorsal integument as a dark median line. 



13 Here a small sucker is also present between this row and the proximal hook. 



