lOG 



AGRIOLIMAX AGRESTIS. 



Fig. 123. 



Fig. 125. 



The REPRODUCTIVE ORGANS have their orifice about two mill, behind the right 

 ommatophore ; the OVOTESTIS is comparatively enormous, and laid upon the upper 

 surface of the digestive gland, 

 the acini being light-brown, with 

 darker connective tissue ; DUCT 

 short and inflated, buff to creamy 

 white, with a slender vesicula 



SKMINALIS ; ALBUMEN GLAND 

 with few lobes, and of a light- 

 brown or .slate colour ; OVISPER- 

 MAf ODUCT broad above, narrow 

 below ; OVIDUCT with ample 

 folds, free oviduct short, with 

 a yellowish glandular invest- 

 ment ; .SPERM. » DUCT slender 

 above, more compact and broad 

 below; VAS DEFERENS short, and 

 entering penis -sheath laterally 

 near the free-end ; PENIS-SHEATH 

 a broad, irregular, and medially 

 constricted sac, with narrow out- 

 let, distal-end with a claw-like 

 digitate gland, which varies 

 greatly in size and complexity, 

 each segment or digit having on 

 its concave side a row of pa- 

 pillai. The lower half of the 

 sheath contains a conical and 

 fleshy SARCOBELUM or excita- 

 tory organ, which 1.=^ often pig- 

 mented at the tip ; the retrac- 

 tor is a short, broad band, 

 arising from the lung floor, to the right of the mid-dorsal line, anterior to both 

 kidney and pericardium, and is attached, not to the apex, but to the middle of the 

 penis-sheath at the same side as the point of entry of the vas deferens ; sperma- 

 THECA fusiform or claviform, attached closely to the base of the oviduct, stem 

 slender, and opening into the narrow and thick-walled atrium, at the junction of 

 the oviduct and penis-sheatli. 



The MANDIBLE or jaw is crescentic in shape, with 

 well and bluntly-rounded ends ; it is a millimetre or 

 more in width, moderately arcuate, of a yellowish- 

 brown colour, and smooth in texture, but showing 

 several distinct darker lines parallel with the upper 

 and lower margins ; median beak or rostrum not 

 prominent, but somewhat acute, its vertical carina 

 not well marked. 



Fig. 124. 



General and detailed illustrations of the reproductive 

 organs of Agriotimax agrestis. 

 Fig. 123. — Flagellate penial gland, showing two of the many 

 variations to which it is liable, X 6. 



Fig. 124. — Reproductive organs, X 2. alb.g. albumen gland ; 

 at. atrium, with protractor muscles ; Ji. flagellate gland ; 

 ot. ovotestis ; ov. oviduct ; p.s. penis-sheath ; r. penis retractor ; 

 sfi. spermatheca ; sp.d. sperm duct. 



Fig. 125. — Penis-sheath laid open, showing point of entry of 

 the vas deferens and the internal structure of the organ, X 4. 

 sh. the sarcobelum or e-vcitatory organ (after Simroth). 



Fig. 126. — Mandible or jaw of 

 A . ai^-rcstis, X 16. (Callander, Penh 

 S., Mr. A. Somerville). 



The LINGUAL MEMBRANE of a Perthshire specimen is 4 mill. long, and IJ mill, 

 wide ; the denticles diminishing in size towards the outer margins ; median teeth 

 with a narrow, posteriorly-expanded base of attachment, the reflection narrow and 

 distinctly tricuspid, the mesocone slender and projecting beyond the basal plate, 

 the eotocones well developed with distinct cuttiug points ; the asymmetrical laterals 

 each have a moderately slender mesocone, the ectocone is also strongly and acutely 

 developed, but the endocone is more or less obsolete, though becoming stronger 

 towards the margin, the seventeenth tooth being distinctly tiicus|iidate ; the mar- 

 ginals are distinctly aculeate, with an incipient ectocone on some of the teeth. 



The foi-mula is \% + i ,» + i + J^"- + ^i^ x 11 8^ 



,378. 



Fig. 12G.— Representative denticles from a transverse row of the Ungual teeth o{ A. ai^cs/fs, X 160, 



The nnimal collected by Mr, A. Somerville, at Callander, Perth S., and the linaual membrane prepared 

 by Mr. j. W, Neville. 



