THE FAUNA OF THE EXE ESTUARY. 329 



the surface, with which its burrow was connected by two, occasionally 

 three narrow passages, which allowed the protrusion of the siphons. 

 The siphons are in large specimens as much as six or seven inches 

 in length. 



SoLEN ENSis, Linnccus. Not uncommon in the smooth sand on the 

 west side of Polesands. This and the succeeding species {S. siliqua) 

 when uncovered by tlie tide very often emerge from the sand and 

 lie on the surface until the tide covers them again. 



SOLEN SILIQUA, Liniueus. This fine Solen was not uncommon on 

 Polesands in the same situation as S. cnsis. 



SOLEN VAGINA, Linnajus. Moderately common on a patch of firm, 

 muddy sand on the west side of the mouth of Salthouse Lake (sta. 10). 

 One from sand on Bullhill Bank (sta. 9). 



Saxicava kuCtOSA, LinncGus. Common boring in Orcombe Eocks. 



Pholas dactylus, Linnccus. Borings common in Orcombe Eocks. 

 Only one specimen was obtained. 



Pholas parva, Pennant. Borings common in Orcombe Eocks. One 

 specimen was taken. 



Patella vulgata, Linnwus. Very common on Orcombe Eocks ; 

 not uncommon on stones between Cockwood and Starcross (sta. 8). 



Troghus magus, Linncvus. Shell only, inhabited by hermit-crab, 

 from Polesands. 



Trochus cinerarius, Linnccus. A few living ones from rough ground 

 on north side of Warren (sta. 12); shells from Orcombe Eocks. 



Trochus UxMBILICATus {Montagu). One living one from Polesands. 



LiTTORiNA littorea (LinnoMis). Found in profusion on Cocklesand, 

 Bullhill Bank, and Greenlands ; not uncommon on the west bank. 

 They are collected by boys, who sell them to the mussel-bed pro- 

 prietors for the purpose of keeping the beds clear from weed. 



EissoA PARVA {Ba Costa). One from Orcombe Eocks and one 

 dredged off the Clock Tower on the sponge ground (sta. 14b). 



Hydrobia ULV.E (Pennant). Occurred practically on all the sandy 

 and muddy grounds where there was Ulva, Unteromorpha , or Zostera, 

 notably on Greenlands (sta. 1) and the muddy ground with weed 

 inside Cocklesand (sta. 13). When left on a bare patch of sand by 

 the receding tide they burrow to a depth of one-eighth of an inch, 

 probably in order to protect themselves from the sun. 



TuRRiTELLA TEREBRA, Linnccus. A shell only, from Polesands. 



Natica CATENA (Da Costa). A dozen or so were found on the smooth 

 sand of Polesands, burrowing just below the surface. 



