Helicoliuiax Lamarcldi. 309 



again at pleasure, by a muscle attached to it behind. It is at the base, 

 where the tube of the bulb perforates the external pouch, a little up on 

 one side, that the orifice of the tube leading from the muscular organ of 

 the matrix is inserted. The structure of the whole will be understood 

 without difficulty from the figures. At fig. 8 the penis and the pouch 

 through which it passes are laid open, so as to shew their structure 

 within. 



It is impossible without having an opportunity of seeing living speci- 

 mens to understand exactly the limits of inversion of the diflferent parts; 

 nor indeed even in Helix does this point seem to have been much studied, 

 from the difficulty of doing it with success. I have merely described the 

 structure, such as I was able to observe it in specimens preserved in 

 spirits, and therefore probably in almost an unnatural state of contraction. 



It remains that I compare the structure with that of the neighbouring 

 genera. IMr. Lowe remarks its near relation with Parmacella. To this 

 conclusion I hadarrived, independently, from the consideration principally 

 of the anatomy. Indeed, in externa! characters alone, the resemblance 

 is too striking to escape notice, and this will be found confirmed by the 

 internal structure. De Ferussac has long ago remarked the extreme 

 resemblance of Parmacella to some HelicoHmaces (Vitrinae). 



First then, compared with Helix, we find the pulmonary and nervous* 

 systems almost identical. The mass of the mouth, tongue, and its main 

 retractor muscle are the same in both. The tooth alone differs slightly. 

 With respect to the stomach, there is in Helix a tendency in this part to 

 put on the form of a double stomach, insomuch that some authors have so 

 described it; the structure in Helicolimax is only a step beyond this; 

 for there is no great difference in the thickness of the coats of the two 

 portions, and indeed when the upper portion is fully drawn out, the 

 difference is the least possible. Besides in Helix the salivary glands, 

 which are very similar to those of the present animal, end just at the 

 point where the slight strangulation of the stomach takes place. I am of 

 course not at liberty to assume the similarity of the liver, or position of 



♦ I did not observe the gang-lions under the origin of the cesophagus which 

 exist in Helix (in Hel. aspersa there are two), but this arose perhaps from my 

 attention not being directed particularly to that point. 

 Vol. V. X. 



