42 



the lower half of the mantle ; this organ has been mistaken 

 for a large foot, but its soft, pulpy, granular composition 

 shows that it is the organ of reproduction, and the milky 

 humours arising from various pyriform membranes, in the 

 genial season, which are only then discoverable, are probably 

 the male organs of fecundation. The colour of the ovarium, 

 as well as of the body in general, is very various ; sometimes 

 they are of a pure vermilion, and from that, passing into every 

 hue of that colour, as well as into all the shades of yellow and 

 pale red-brown. I have seen all these colours in groups of 

 the Anomia ephippium, on the same Pecten -, whilst in others 

 all the objects on the same shell have maintained a uniformity 

 of colour. The same discrepancies prevail in A. aculeata, 

 A. striolata, A. cylindrica, and A. squamula. These differ- 

 ences, combined with the various markings, shapes, spines, 

 ribs, and striae, generally resulting from similar markings on 

 the substances on which the shells are fixed, have doubtless 

 been the cause of the multiplication of the species, as in all 

 the varieties enumerated, not excepting the A. striata, which 

 is the A. patelliformis of the ( British Mollusca/ the organs, 

 as far as they have been examined, have not presented marked 

 differences, except in colour. The liver is always of the va- 

 rious shades of green, placed under the beaks, at the centre of 

 the dorsal range ; the passage from the mouth to the stomach 

 is a short gullet, and these organs are situate under, and 

 partly surrounded by the liver ; from it the intestine descends 

 to the centre of the body, where it makes some turns, then 

 ascends through it and the ovarium to the dorsal range, and 

 issuing therefrom, passes behind the body and the posterior 

 sinuation of the ovary, slightly attached to their membranes, 

 and debouches at some distance from the base of the posterior 

 ventral range, as an uncovered rectum. 



In most bivalves the muscular impressions are supposed to 

 assist specific distinction, but this idea is fallacious with re- 

 spect to the Anomia. In this genus the circumscribed line 

 in the convex valve contains the impressions of the muscular 

 mass, which divides itself into three cicatrices, one by itself 

 and the others on the right and left of it ; these impressions 



