NOTES — MOLLUSCA. 



79 



L. peregra m. decollatuni and Bythinia tentaculata 

 m. decollatum in Cheshire.— I noted the occurrence of L. peregra m. 



decollatuni about April last, in a pond near Chester Canal. The form was small,, 

 elongated, and rather thin. Apparently feeding on the thick green growth which 

 half choked the pond. 



Later on I found Bythinia tentaculata m. decollatuni in a ditch, which, though 

 near this pond, had no communication with it ; while it was accompanied by 

 ordinary sized L. peregra, slightly inclined perhaps to var. ovata, but not decollate. 

 What I wish to note is the occurrence of these two species decollate in neighbour- 

 ing pools, while on the other hand the L. peregra occurring with B. tentaculata 

 were of normal growth. — Brockton Tomlin, Pembroke College, Cambridge, 

 November 15th, 1885. 



Pupa marginata var. brevis (Baudon) in Yorkshire.— Amongst 



some shells collected by Mr. W. Denison Roebuck on June 27th, 1885, at Runs- 

 wick Bay, near Whitby, I found a very characteristic specimen of this variety, 

 which has not previously been recorded as British. It is described by Baudon as 

 ' Tres raccourcie, robuste, bourrelet epais, blanc au peristome.' The average size 

 of the type as given by Dr. Jeffreys is o'i33, or about 3% mm., and breadth o*6, 

 the latter presumably an error for 0*06 which is equal to about 1 14 mm. The 

 specimen of var. brez'is is 2 mm. long and about i^mm. broad, is composed of a 

 whorl less than usual, and the mouth being perfectly finished shows it to belong to 

 the edentate form of the species. — J. W. Taylor, Leeds. 



Mollusea at Louth, North Lincolnshire. — In September last I 



began to work at the mollusea of this district, and since then have found 31 

 species ; 9 of which were not recorded for North Lincolnshire (vice-county 54) in 

 the 'census" published in the Journal of Conchology in 1885. 



H. rufescens is the commonest Helix here. Sphcerium corneum, Planorbis 

 spirorbis, Planorbis vortex, Physa fontinalis, Limncea peregra var. ovata, Aricn 

 ater, Arion hortensis and var. grisea, Li max agrestis and var. sylvatica, Limax 

 arborum (mostly on beeches' 1 , Helix aspersa, H. nemoralis, H. hispida, and 

 H. rotundata are common and generally distributed throughout the district. 

 Bythinia tentaculata, Valvaia piscinalis, Planorbis cariuatus, and Planorbis 

 contortus are found in the Louth Canal. Anodotita cygnea is common in the 

 canal, and in a large sheet of water known as Burwell fish-pond ; 5% inches is 

 the largest measurement found as yet. Ail the specimens of Limncea peregra, both 

 from ponds and streams, are. referable to var. ovata, with the exception of some 

 from a brick-pit in the village of South Reston, which are Limticea peregra 

 proper. Mr. Cockerell of Bedford Park returns one specimen from a quick- 

 running stream as Lim. peregra var. (not ovata). Full-grown specimens of 

 Limncea stagnalis swarm in a little stream known as Monk's Dyke; most of these 

 on being lifted out of the water discharged their violet-coloured liquid. This 

 species is also found in the canal. Limncea palustris is plentiful in water which 

 collects under some willow trees during the winter months, and is also found in 

 the canal. Ancylus fluviatilis adheres to the stones in clear quick-running 

 streams. Zonites cellarius, Z. glaber, and Z. nitidulus are not uncommon. 

 Helix arbusto7-um has been found in several situations in this neighbourhood, but 

 is most plentiful on a hedge-bank in the village of Hallington. Helix ericetorum 

 has been found in four places, and swarms on a certain chalky bank, where also 

 Helix caperata is abundant. Bulimus obscurus occurs on the trunks of trees, and 

 under moss. Balea perversa I have as yet only found on ash. Clausilia rugosa 

 is very abundant, and appears to be commonest on the trunks of beech and 

 hawthorn. 



The following varieties have also been found, and kindly named for me by 

 Mr. T. D. A. Cockerell of Bedford Park. Arion ater var. bicolor, immature 

 (among Tussilago farfara in a chalk pit) ; Limax arborum var. bettouii, Helix 

 aspersa var. minor, Hdix nemoralis vars. libellula and rubella (with various band, 

 formulce), Helix arbustorum var. conoidea and var. approaching marmorata. Helix 

 hispida var. subrufa and var. nana, Helix caperata var. major and var. oruata- 

 and Helix ericetorum, var. approaching alba. — H. WALLIS Kew, Louth. 

 February 1886. 



March 1886. 



