So 



THE FEEDING TRACK OF OXYSTELE IMPERVIA Menke. 



By KEPPEL H. BARNARD, B.A. 



(Read before the Society, September nth, 1912). 



Observations on the feeding tracks of gasteropods are not numerous. 

 L. E. Adams ywCn^ Journal of CojicJiologyiox^wXy, 19 12, has described 

 the track of Z/;;m.v 7?r?z7/i- and B. B. Woodward ("Proc. Mai. Soc, 

 vol. vii., no. i, March, 1906) has recorded' tlie track left by a slug 

 on a bromide print and has enumerated the previous records. 

 The following note on the tracks of Oxystele iinpervia Menke, a 

 common Cape species, may therefore be interesting. The tracks were 

 on the glass of an aquarium tank just below the water-line and showed 



iinii 



Portion of the feeding tract of Oxystele iinpervia^ about natural size. 



very plainly when the water was removed. They consisted of very 

 regular series of alternate sweeps, each sweep being formed of 18 (on 

 an average, the extremes were 14 and 22) individual "licks." The 

 sweeps measured from 20-25 '^'^- i" width and the licks 2 mm. by 

 I mm. All efforts to obtain an "autograph" by inducing the animal 

 to feed off the sensitised film of a photograph (see "Woodward, I.e.) 

 were failures. I hope to obtain the tracks of other species, e.g., the 

 much larger Oxystele tigrina and Turbo sarmaticus. 



Note on a Sinistral Specimen of Marginella zonata Kiener. — Whilst 

 travelling in South Africa my friend, Mr. G. Butler, was endeavouring to procure 

 some shells for me, and staying with some friends of his got a small parcel of shells 

 picked up on the beach at Cape Town. On examining the shells I was agreeably 

 surprised to find an immature sinistral specimen of M. zonata, other specimens of 

 the type and var. were all dextral. A sinistral specimen of J/, apicina Menke — 

 var. conoidalis Kien.— is in the collection of Dr. J. Cosmo Melvill, and sinistral 

 forms of M. glabella L. have, I am informed, been reported. -^B. R. Lucas 

 (^^fl^^^;if///£6'^«V/j', March I2th, 1913). 



