1895.] HYDEACHNID FOI7?fD IX CORNWALL. 197 



organs in my species fairly correspond with those described by 

 Schaub ; but here the resemblance suddenly ceases : instead of 

 the large simple bundle of striped muscles filling up the interior 

 of the cap and arising from the other genital organs, we have an 

 entire absence of muscles within the cap, although some small 

 muscles are attached round it. The inner side of the chitinous 

 cap rests upon the distal ends of a number of columnar radi- 

 ating cells forming an even layer about "OlS mm. thick ; these 

 cells take stain A-ery deeply and rapidly, so much so that it is 

 difficult to prevent their staining too darkly if other parts are to 

 be stained at all. The proximal ends of these cells rest upon a 

 basal membrane {mh.) about -003 mm. thick, which does not stain 

 at all, and which is continuous Avith the external membrane of a 

 solid pyriform mass of large elongated cells. Each cell is largest 

 at its inner extremity and diminishes outward. All the cells con- 

 verge toward the smallest part of the organ, i. e. the point where 

 it passes through the hole in the cuticle ; they then spread out 

 again a trifle, and their distal ends abut on the inner side of the 

 basal membrane before mentioned ; the distal portion of each cell, 

 i. e. the part between the hole in the cuticle and the basal mem- 

 brane, stains darkly and rapidly ; the rest of the cell much more 

 slightly and slowly. Each cell near its larger (inner) end contains 

 a large clearly defined nucleus with a distinct nucleolus, those in 

 the respective cells being very regularly arranged. 



The whole organ has a formation entirely different fi'om what 

 would be expected in a sucker, and indeed has much more the 

 appearance of a sense-organ of some kind ; e. g. it looks not unlike 

 the simple ocellus of an insect. I do not for a moment suggest 

 that such is its function ; such a thing would be unlikely in the 

 extreme ; and I do not detect any sufficient nerve-supply to justify 

 it if it were not ; but I do suggest that, in this species at all 

 events, the organs are not suckers, and that it seems not impos- 

 sible that they may have some sensory function. It struck me at 

 first whether they could be glandular, but I do not find any point 

 of discharge, nor any signs of cells breaking down and emitting 

 their contents ; and it has to be remembered that they are present 

 equally developed in both sexes. Of course I at once admit that 

 the position of the organs is such as to render it most probable 

 that they perform some office in connection with the genital 

 organs. 



Glands of unknown Function (Plate IX. fig. 28). 



Lying immediately below the lateral portions of the hollow 

 square of the ventriculus, immediately above the genital organs in 

 both sexes, and about the middle (longitudinally) of the latter 

 organs, exist a pair of almost globular, or slightly elliptical, organs 

 of about -04 mm. diameter in the male and about -05 to •! mm. in 

 the female. These organs (fig. 19, gu.) have every appearance 

 of being glands ; they are composed of distinctly-nucleated closely- 



