472 PROCEEDINGS OP THE ACADEMY OP 



Gastrochaena, (including both Gastrochaena and Rocellaria.) 

 Spengler, Nov. Act. Sc. Soc. Havn. ii. 1780. 

 Blainville, Malacol. i. p. 574, 1825. 

 Deshayes, Traite Elem. i. pt. 2, p. 26, 1843 '50. 

 Chaena, (partim,) Retzius, Nov. Test. Gen. p. 19, 1788. 



Gray, Figs. Moll. Anim. v. 1857. 

 Mya, (partim, ) Pennant, Brit. Zool. iv. 1777. 



Donovan, Brit. Shells, iii. 1801. 

 Montagu, Test. Brit. i. 1803. 

 Maton & Rackett, Linn. Trans, viii. 1807. 

 Wood, Gen. Conch, edit. 1, 1815. 



" Index Test, edit. 1, 1818 ; edit. 2, 1828. 

 De Gerville. Cat. des Coq. de la Manche, 1825. 

 Chama, DaCosta, Brit. Conch. 1778. 

 Pholas, (partim,) Chemnitz, Conch. Cab. x. 178S. 

 Gmelin, Syst. Nat. i. 1790. 

 Poli, Test. utr. Sicil. i. 1791. 

 Olivi, Adriatica, 1792. 



Schreibers, Versuch nach Conchylien, ii. 1793. 

 Pultney, Dorsetshire Catalogue, 1799. 

 Dillwyn, Descriptive Catalogue, i. 1817. 

 Wood, Gen. Conch, ed. 1, 1815. 



" Index Test, edit. 1. 1818 ; edit. 2, 1828. 

 Mytilus, (partim,) Dillwyn, Descriptive Catalogue, i. 1817. 

 Fistulana, (partim,) Bosc, Hist. Nat. des Coq. ii. p. 205, 1824. 



Deshayes, Encyc. Meth. Vers. ii. p. 139, 1830. 

 Philippi, Enum. Moll. Sicil. i. p. 2, 1836. 



Description. Shell regular, equivalve ; valves ovate or cuneiform, widely 

 gaping anteriorly, very inequilateral ; umbones anterior, ligament long and 

 narrow. Pallial line lightly impressed, sinuated, uniting the muscular im- 

 pressions. 



Tube claviform or irregular, often incomplete, perforating shells and lime- 

 stone, to which its walls are sometimes adherent. 



Subgenus Spengleria, Tryon. 1861. 



I propose to separate from Rocellaria those species which are elongate- 

 cuneiform, truncated at the posterior end of the shell, and having a triangular 

 space, radiating from the beaks posteriorly to the margin, elevated slightly above 

 the general surface of the shell, and ornamented with transverse lamellae. 



3. Genus Cucurbitpla, Gould. 1861. 



Cucurbitula, Gould, Proc. Bost. Soc. Nat. Hist. viii. p. 22, March, 1861. 



Fistulana, 1 



Gastrochrena, > Partim. of authors. 



Chaena, &c. y 



'" Description. Shell regular, elongate, equivalve, gaping the whole length, 

 anteriorly enveloped by the mantle of the animal. 



Tube very short, ovate, or gourd-shaped, composed of successive calcareous 

 layers or cups, involving bits of shell or sand. Attached by one side to 

 shells, &c. 



I quite agree with Dr. Gould in the propriety of erecting a new genus for the 

 well known Gastrochaena 1 a g e n u 1 a. The characters given above prove it to 

 be quite distinct from Gastrochaena or Rocellaria. 



Subfamily 2. BRYOPINiE, Tryon. 1861. 

 Shell with the right valve only free, the left being imbedded in the tube. 



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