206 THE F\UNA OF THE SALCOMUE ESTUARY. 



Thracia PHASEOLINA, Lamarck. One living specimen was found 

 lying on the sand at Millbay. 



SOLEN MARGINATUS, Pulteney. This species is characteristic of the 

 sand and zostera banks between Millbay and the Ferry House, being 

 most abundant at the Millbay end in the sand. It burrows to a depth 

 of eighteen inches or so, the hole being easily recognised by the shape of 

 its aperture, which is oblong with a slight constriction in the middle. 

 The animal is able to disappear down its hole much more quickly than 

 S. ensis, owing probably to its shell being straight and not curved. 

 When annoyed it frequently throws off its siphon in rings, the siphon 

 splitting along the dark transverse bands which mark its surface. 



SoLEN SILIQUA, Lmnceiis. A few specimens only of this species were 

 found in the sand at Millbay. The aperture of the hole is oval in 

 shape. 



SoLEN ENSIS, Lmnceiis. A few shells only of this species were found. 

 It seems to prefer a much coarser sand than S. marginatus, as the only 

 place near Plymouth in which it occurs in abundance is a bank in 

 the Eiver Yealm, which consists of much coarser sand than that at 

 Millbay, Salcombe. Although we have collected in the Yealm many 

 times, so far we have only found one S. marginatus. 



SoLEN PELLUCIDUS, Pennant. Several specimens of this small Solen 

 were found lying on the surface of the sand at Millbay just after 

 the tide had turned, having come out of their holes. One large one 

 was obtained from the mud on the north-east of the Salstone. When 

 placed in a dish of sea-water the small specimens became active at 

 times, swimming or shooting about in search of a suitable place in 

 which to burrow. The swimming was effected by means of the foot, 

 which was protruded at the end of the shell, bent back over one of 

 the valves to its fullest extent, and then suddenly straightened. The 

 impetus received from the action was frequently sufficient to propel 

 the Solen two or three inches. This movement was often repeated 

 several times, after which the animal would attempt to burrow, again 

 making use of its foot, which it straightened out, keeping it at the 

 same time as thin as possible and forcing it into the sand. After 

 entering the sand the end of the foot was first of all expanded, and 

 then the whole foot contracted, the shell being thus drawn a little 

 way beneath the surface. This action was repeated until the Solen had 

 buried itself. When lying in sea-water on the bare glass it still tried 

 to burrow in the same way, often making several attempts at one spot. 



Tellina ingarnata, Linnmus. Shells only were found. 



Tkllina fabula, Gronovius. A living specimen was found in the 

 zostera bank under the Marine Hotel, buried six or eight inches below 

 the surface. 



