34 LEPADID.E. 



within the peduncle, till they expand into two small 

 organs, which I have called cement-glands. These glands 

 are found with great difficulty, except in Conchoderma 

 aurita, where they are placed on each side under the inner 

 layer of corium, at the bottom of the sack, so as to be just 

 above the top of the peduncle ; they resemble in shape a 

 retort, (PI. IX, fig. 3.) In Potticipes mitella and polymer us 

 they lie half way down the peduncle, close together, 

 and apparently enclosed within a common membrane; in 

 these two species the broad end of the gland is bent 

 towards the neck of the retort. In Scalpellum the position 

 is the same, but the shape is more globular. In Ibla the 

 structure is more simple, namely, a tube slightly enlarged, 

 running downwards, bent a little upwards, and then 

 resuming its former downward course, the lower portion 

 forming the duct. The gland contains a strongly co- 

 herent, pulpy, opaque, cellular mass, like that in the 

 cement-ducts ; but in some instances, presently to be 

 mentioned, this cellular mass becomes converted within 

 either the ducts or gland, or within both, into transparent, 

 yellow, tough cement. Generally in Conchoderma, Pol- 

 licipes, and Scalpellum, two ovarian tubes, but in one 

 specimen of Conchoderma aurita, three tubes, and in Ibla 

 one tube could be seen running into or forming the 

 gland ; of the nature of the tubes there could not be the 

 least doubt, for at a little distance from the glands they 

 gave out branches (PL IX, fig. 3), containing ova in every 

 state of development. In some specimens as in that 

 figured of Conchoderma aurita,the ovarian tube on one side 

 of the gland is larger than on the other, and has rather 

 the appearance of being deeply embedded in the gland 

 than of forming it; but, in other specimens, the two 

 ovarian tubes first formed a little pouch, into which their 

 cellular contents could be clearly seen to enter ; and then 

 this pouch expanded into the gland ; thus quite removing 

 a doubt which I had sometimes felt, whether the ovarian 

 tube was not simply attached to or embedded in the 

 gland, without any further connection. By dissection 



