S L E N. 



Plate I. 



Genus SOLEN, Liiinceiis. 



Testa CBquivalvis, transverse clongata, recta, vel lente 

 arcuata, utrinqui plus tninusve tnmcata, hians, 

 umhonihus terminalibits. Cardo elongatus, dentibus 

 uno et diiohus principalibus. Ligamenium externum. 

 Impressio nvuscularis antica elongata. Impressio 

 pallii ad terminum quadralim simiata. 



Shell equivalve, transversely elongated, straight, or 

 slightly arched, more or less truncated, gaping, 

 with terminal umbones. Hinge elongated, with 

 one and two principal teeth. Ligament external. 

 Anterior muscular imi)ression elongated. Palleal 

 impression with a square sinus. 



There would seem to be no sullicient reason to 

 separate generically the straight from the curved razor- 

 shells. United, they form a capital genus, distinguished 

 from others of the family by having terminal beaks. The 

 shell is also divided into two more or less distinct areas 

 by a diagonal line from the apex at the anterior to the 

 posterior lower corner of the truncated [uisterior 

 extremity. 



The habits of the Solens are peculiar. They furm 

 deep burrows in the sand, into and out of which they 

 spring with amazing rajiidity by a sudden contraction 

 and expansion of the foot. They can also leap forward 

 with great power. They are found in most tem- 

 perate and tropical countries, but no country possesses 

 many species. On the coasts of Britain we have 

 several well-kno\vn species ; Mr. Cuming found several 

 in the Philippines, but most of them are scattered singly 

 in almost as many countries as species. 



j truncated obliquely and sharply at the anterior 



j end, with the antero-ventral angle acute. 



SowERBT. Genera of Shells. 



Ceylonensis, Dunker. 



Hub. Ceylon. 



Solcn irunccilus, including the varieties, forms a very 

 good and easily recognisable sjiocies. 



Species 1. (Mus. Brit.) 



SoLEN TiiUNCATDS. Sol. testo. laid, rectd, suhcompressd, 

 fasciis purpureis strigatd, ad terminuiu jwsticum 

 late et perpendiculariter truncatd ; ad terminum 

 anticum oblique et acute truncatd, angulo antico- 

 ventrali acuta. 



The truncated Solen. Shell broad, straight, sub- 

 compressed, striped with purple bands, truncated 

 broadly and perpendicularly at the posterior enil ; 



Species 2. (Mus. Soworby.) 



Solen \-agixa. Sol. testa rertiusculd, elongatd, sub- 

 depressd, versus umbones subrosed, antice suboblique 

 pautd arcuald, postici; suboblique truncatd ; margine 

 ventrali vi.i- coarctalo ; margine dorsali medio paidb 

 elerato. 



The sueath Solkn. Shell rather straight, elongated, 

 subdepressod, rather pink towards the umbones, 

 anteriorly subobliquely truncated ; ventral margin 

 scarcely contracted ; dorsal margin a little raised in 

 the middle. 



LiNNJEUs. Systenia Naturte. 



Ilab. Great Britain. 



A well-known .species, tlie largest of the true Solens. 



Species 3. (Mus. Brit) 



Solen ensis. Sol. testa angustiiiscnld, arcuatd, de- 

 pressd, subtus epidermide pallide rosed vel grised 

 strigatd, ad terminum anticum subrotundd, ad 

 terminum posticnm recti: truncatd ; margine dorsali 

 arcuatim excavato ; margine ventrali arcuatim con- 

 vexd. 



The sword Solen. Shell very narrow, curved, 

 depressed, striped with pale rose or grey beneath 

 the epidermis, sti-aightly truncated at the posterior 

 end ; a little rounded at the anterior end ; dorsal 

 margin sloped out in a curve; ventral margin 

 convex in an arch. 



LiNNiEOS. Systema Naturae. 



Siliqua ensis. Schumacher. 



Hab. Great Britain. 



August, 1874. 



