The structure of the ovotestis of the common African land snails found in Abeokuta, South Western Nigeria.

Résumé

A comparative study of the structure of the ovotestis of African land snails found in Abeokuta was investigated. Of all the five snails species found and dissected, Archachatina marginata, Achatina achatina, A. fulica, Helix pomatia and Limcolaria aurora, only the ovotestis of H. pomatia could not be observed. The positioning, shape and arrangement of the ovotestis was the same for all the other four species. The ovotestis is embedded in the digestive gland at the anterior region of the coiled posterior end of the visceral mass. It is cream coloured and made up of sac-like lobes arranged on a single plane. It is differentiated into an ovariaon and testicular region. The number and size of the ovotestis differ significantly (P<0.05) in all the snails. Each lobe is made of several follicles and the number of which varied in the four species. Statistical analysis showed that live weight, shell length, shell width and shell circumference of the snails had no significant influence on the size on their ovotestis. Meiotic metaphase spreads of the ovotestis tissues revealed chromosome numbers 2n=56, 2n=44, 2n=54 and 2n=28 for A. marginata, A. achatina, A. fulica and L. aurora