266 LAWSON, ON HELIX ASPERSA AND HORTENSIS. 



involutus.) Examined microscopically^ nothing resembling a 

 second tube included Avithin 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 prov<^ 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 ap- 

 parently 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 con- 

 fused 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 ol 

 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 sac- 

 culated 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 zigzag 

 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 sacculi above described ; 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 saKvary glands on its left. 

 At the period of depositing the eggs this vessel becomes 

 enormously distended, the sacs appearing much more distinct 

 than usual, each containing its large ovum, and separated 

 from its neighbour by a Avell-marked constriction. I am 

 inclined to agree with Turpin, in believing that the uterus 

 secretes those beautiful rhombic crystals of carbonate of lime 

 seen on the egg of this animal, inasmuch as I have not found 

 them upon those ova which had just entered the upper sacculi, 

 whilst those situate in the lower ones were invariably studded 

 with them. 



The male organs lie to the left of the female, and include 

 the testis, vas deferens, and penis, with its flagellum. The 

 first, as before mentioned, is closely united to the uterus, 

 commencing and terminating with it ; nevertheless, it is a 



