GENUS MILAX. 137 



which is in advance ; the eeproductivb orifice is situate mid-way 

 between the base of the right ommatophore and the respiratory orifice. 

 The ORGAN OF SEMPER is externally perceptible as crenulations or pucker- 

 ings of the upper lip, which presents a row of eight or more rounded 

 papillfe. 



Internally, the viscera show a strong spiral twist' in a sinistral direc- 

 tion, the amount of torsion corresponding somewhat to that of a dextrally 

 coiled Buliminus. The reproductive organs do not loop the retractor of 

 the right tentacle, and possess a very remarkable series of accessory glands 

 adherent to the base of the oviduct and atrium, into which they debouch 

 by numerous slender ducts ; there is no flagellum, but a well-marked epi- 

 phallus, within which a spermatophore is developed, and which is basally 

 separated from the penis by a well-marked sphincter muscle. The penis- 

 retractor arises from the dorsal skin on the right-side, just below the root 

 of the cephalic retractor, and is attached to the epiphallus. The sarco- 

 BELUM, or excitatory organ, though present in our British species, is not 

 an invariable character in all the species of the genus ; the Milax 

 carinatus of southern Europe, which in other respects is so closely related 

 to our Milax soiverbii, is said by Lessona & PoUonera to be destitute of 

 an excitatory organ, though Dr. Simroth found it present in a Florentine 

 specimen forwarded by Signer Lessona. The kidney is somewhat oval in 

 shape, and differs from that of Limax in having a linguiform prolongation, 

 doubled back under the organ and protruding behind on the right side. 

 The SUPRA-PEDAL GLAND lies free in the body cavity, and is only about 

 one-third the total length of the body. 



The CEPHALIC RETRACTORS Comprise the pharyngeal and tentacular 

 muscles, which are usually separate nearly or quite to their roots, though 

 their points of origin are always closely contiguous ; they arise from the 

 dorsum, beneath the floor of the shell sac, to which they are firmly 

 attached, exactly at or near to the point where the shell is adherent by 

 its apex to the floor of the pouch. 



The FOOT-SOLE is distinctly longitudinally tri- 

 partite, the broad mid-area being bounded by a 

 well-marked groove at each side, and the wrinklings 

 formed during the contraction of the sole, unlike 

 those of the true Limaces and A griolimaces, which 

 are simply transverse, show in Milax a striking 

 chevron-like character in the median -line, an 

 arrangement said to tally accurately with the dis- Fig. isi.— Diagram of the 

 position of the lateral branches of the sympathetic [he'ch°evro°n-sha.p2d'trans"er"l 



mesh of the pedal nerves. wrinklings of the median-area. 



The law of colouring is similar to that pertaining to A. agrestls; the 

 animals darken with age, the darker mantle-markings being assumed to be 

 ancestral traits not yet obliterated, and formed by the approximation and 

 fusion of the isolated spots of young animals. The primitive colouring of 

 the species of this group is supposed to be simple, and just as A. agrestis 

 shows unicolorous dark or slate-blue varieties on the Mediterranean 

 shores, Milax has developed a preponderance of dark unicolored species 

 or varieties in similar situations. 



In the eastern Mediterranean region, Milax is separable into the species 

 furnished with a prominent dorsal keel and those in which the keel is 

 confined to the caudal end of the body ; the latter, which form the section 



1 Monog. i., p. 282, f. 563. 

 29/5/04 ' 



