38 



Wood, Wm General Conchology, ed. 1, 1815. 



Index Testaceologicus, edit. 1, 1818 ; edit. 2, 1828. 



Woodarch Introduction, 1831. 



Woodward, S. P Manual of Mollusca, part ii. 1854. 



Wyatt, Thos Conchology, 1838. 



Classification. 



CONCHIFERA. 



PHOLADACEA. 



(Family I. PHOLADIDsE.) 



Family II. GASTROCE^NID^E. 



Shell. — Valves thin, gaping, edentulous, or teeth rudimentary, ligament 

 external, adductor impressions two, pallial line sinuated ; contained within a 

 shelly tube, both valves free, or one or both valves cemented to its walls. 



Animal. — Symmetrical, elongated, anteriorly truncated ; with two long con- 

 tractile siphons posteriorly, united nearly to their extremities, which are 

 fringed with cirrated orifices. Margins of the mantle anteriorly thickened and 

 united, with a small pedal opening ; foot cylindrical, small ; gills, a pair on 

 either side, prolonged into the branchial siphon. 



Frequently gregarious ; burrowing in wood, stone, sand, or mud at low 

 water mark, and lining their burrows with a calcareous tube ; the shape of 

 which, together with the more or less cohesion of the valves to its sides, 

 affords the generic characters. 



Subfamily 1. GASTROCHiENINJE, Tryon, (not Gray.*) 1861. 



Shell with both valves free from the tube. 



a. Inequivalve, edentulous ; tube straight, striated transversely, and fur- 

 nished, when complete, with a perforated septum behind the valves. 



> 1. Genus Gastkoch^na, Spengler. 1780. 

 Gastrochrena, (including Rocellaria.) 



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

 Blainville, Malacologie, p. 574, 1825. 

 Rang, Tabl. Meth. p. 342, 1829. 

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

 Gastrochama, (as at present restricted.) 

 Morch, Catalogue, 1853. 

 H. and A. Adams, Genera, ii. p. 334, 1856. 

 Chrena, Retzius, Nov. Test. Gen. p. 19, 1788, (including Rocellaria.) 



Schumacher, Essai d'un Nov. Syst. p. 94, 1817, (including Rocellaria.) 

 Gray, Zool. Proc. London, p. 189, 1847. 

 " " " " p. 315, 1858. 



Deshayes, Zool. Proc. London, p. 330, 1854. 



Woodward, Manual, p. 326, 1854, (as a subgenus of Gastrochsena, 

 Rocellaria.) 

 Fistulana, Bruguiere, Encyc. Meth. Vers. 1789. 



Cuvier, Regne Anim. Ed. primo, ii. p. 494, 1817. 

 Lamarck, Anim. Sans. Vert. v. p. 432, 1818. 



" (Deshayes' edit.) Anim. Sans. Vert. vi. p. 25, 1835. 



* Gray's subfamily Gastroch;enaina is made to include only the species of Rocellaria, 

 (by him wrongly named Gastroch<ena,) while the genus Gastrochana he has placed, under 

 the name of Ghana, in another subfamily Ch.enaina. I include the two genera in one 

 subfamily. I also include a third genus, recently proposed by Dr. Gould. 



