54 DUBLIN NATURAL HISTORY SOCIETY. 



ments, it measures at its widest part about three-eighths of an inch ; 

 whilst from Avithin outwards, it is about a quarter of an inch. It is 

 composed of numerous branching coeca, or lobules, of a light-yellowish 

 colour, bound together hj folds of a delicate areolar, or fibrous mem- 

 brane. A portion placed under the microscope presents the appearance 

 of a follicle, secreting from its inner wall numerous oval, or spherical, 

 nucleated cells, and having occasionally within it, and rather near its 

 mouth, a few isolated /oosperms — no trace whatever of a second sac 

 invaginated by the former can be observed. The ducts of the various 

 lobules unite toward the apex of the organ, and form a common chan- 

 nel — the oviduct. This vessel bends its course in a spiral direction, 

 from the ovary to the albumen-gland. It is simple at both extremities, 

 but very much convoluted in the interval. It is about seven-eighths of 

 an inch in length ; and before it terminates in the sinus of the albumen- 

 gland, it makes a slight spur-like turn backwards. (I have not seen 

 any of those decided projections on its convoluted portion, which Pro- 

 fessor Goodsir has described as existing in Lymneus involutus.) Examined 

 microscopically, nothing resembling a second tube included within the 

 duct is to be seen. The albumen-gland is a large, homogeneous-looking 

 structure, in shape like a boat, situated in the first spire of the shell, 

 of which it occupies one-half. It lies beneath the lung, rectum, heart, 

 and urine-gland. Its concave surface embraces the second spire, whilst 

 its keel is bounded externally by the liver, into which its apex or prow 

 also projects, its base or stern being attached to the upper extremity of 

 the uterus. It measures about an inch in length, and is composed 

 apparently of two distinct portions, an opaque and a translucent. It is 

 very difficult, if not impossible, to ascertain its minute structure. A 

 central duct traverses its substance, which would seem to collect from 

 others more minute the peculiar gelatinous secretion. Viewed under 

 the microscope, a confused chaos of spherical albumen -globules and 

 minute fibres is observed. I have not found any zoosperms in this 

 organ. The sinus is a membranous expansion, formed at the point of 

 junction of this gland with the uterus ; into it the oviduct passes, after 

 having been lodged for some short distance in the substance of the 

 albumen-gland. The uterus is a sacculated duct, measuring usually an 

 inch and a half in length, and being fully one-eighth of an inch in 

 calibre. Starting from the last-named gland, it makes two or three 

 zig-zag turns, and ends as a cylindrical vessel in the vagina. It is 

 closely adherent along its whole length, to the testis which lies on its 

 left border, and which, being shorter than the uterus itself would be 

 if isolated, has the effect of producing the various saccali above de- 

 scribed ; so that the two together have not been inaptly compared to 

 the intestine supported by its mesentery. It is situated upon the 

 powerful muscles of the foot, and has the gullet and salivary-glands on 

 its left. At the period of depositing the eggs, this vessel becomes enor- 

 mously distended, the sacs appearing much more distinct than usual, 

 each containing its large ovum, and separated from its neighbour by a 

 well-marked constriction. I am inclined to agree with Turpin, in 



