SCATOLOGICAL STUDIES OF THE BIVALVIA (MOLLUSCA)
40 1
rough comparison between the nature of the rectum and that of the
stomach type, they suggest, further, that the distribution of the anisomyarian rectum (except for the Pectinacea which have a Type 4
stomach) is identical with that of the stomach Type 3 and not of the
ctenidium-palp association (Stasek, 1963).
Fig. 18. Mid-gut and anus in Anadara subcrenata. Top : Mid-gut (cross-section) ( x 30) ;
bottom : Anus ( x 12).
These findings demonstrate that the bivalve rectum is concerned in
determining the final characteristics of the faecal pellets.
Though these investigations need to be carried out on a much
larger scale, the general conclusion to be drawn is that the structure
40 1
rough comparison between the nature of the rectum and that of the
stomach type, they suggest, further, that the distribution of the anisomyarian rectum (except for the Pectinacea which have a Type 4
stomach) is identical with that of the stomach Type 3 and not of the
ctenidium-palp association (Stasek, 1963).
Fig. 18. Mid-gut and anus in Anadara subcrenata. Top : Mid-gut (cross-section) ( x 30) ;
bottom : Anus ( x 12).
These findings demonstrate that the bivalve rectum is concerned in
determining the final characteristics of the faecal pellets.
Though these investigations need to be carried out on a much
larger scale, the general conclusion to be drawn is that the structure