Egg and early stages of development of Spermodea lamellata

Although not of high quality I thought members might like to see the accompanying photographs of the egg and early stages of development of Spermodea lamellata. Adult snails were found in a leaf litter sample collected from Saltburn Gill, North East Yorkshire (grid ref. NZ675207) on 19th May 2007. These were held temporarily until the following August by which time they had bred. The photographs were taken on 16th August 2007. The first photograph shows an egg just before hatching, an individual in the process of hatching and one newly hatched in which the characteristic shell lamellae have started to develop. The second shows two older individuals in which the lamellae are further developed. The photographs were taken under artificial lighting, through one eyepiece of a binocular microscope, using a 5megapixel Nikon digital camera.