356 Zoological Society. 



Arca virescens. Area testa elongatd, lateribus rotundatis, postico 

 leviter angulato, antico subattenuato ; viridescente, epidermide 

 tenui, ad aream posiicam setosd, itidutd ; striis elevatis radiatd ; 

 ligamenti ared ongustissimd, mnbonibiis approximatis. 

 Conch. Icon. Arca, pi. 15. f. 97. 



Hab. Catbalonga, island of Sarnar, Philippines (found under stones 

 at low water) ; Cuming. 



A delicate greenish species, in which the epidermis lies on the 

 posterior area in rows of line bristles. 



Arca fasciata. Arca testa oblongd, tenui, compressd, lateribus 

 rotundatis, superne attenuatis ; albidd,fasciis cinereo-jmrpurascen- 

 tibiis indistinctis concentrice tinctd ; epidermide tenui, postice se- 

 tosd, indutd; radiatim striata, striis elevatis, irregidaribus, striis 

 transversis subtilissimis fimbriato-decussatis ; ligamenti ared an- 

 gustd, profunde declivi ; intus purpurascente . 



Conch. Icon. Arca, pi. 15. f. 99. 



Hab. } 



This is a remarkably flattened shell, banded and stained with red- 

 dish and ashy purple both inside and outside. 



Arca lima. Arca testa elongato-ovatd, lateribus superne angulatis, 

 antico infra rotundato, postico angulato-rotundato , subeoctenso ; 

 fuscescente, fusco tinctd, postice fusco maculatd, epidermide tenui 

 subtilissime setosd indutd, radiatim liratd, liris angustis, numero- 

 sis, confertis, granosis, perpaucis medianis duplicatis ; lateraliter 

 costatd, costis rudibus, subdistantibus, crenato-nodosis ; ligamenti 

 ared angiistd. 

 Conch. Icon. Arca, pi. 15. f. 101. 



Hab. Islands of Burias and Corregidor, Philippines (found under 

 stones at low water) ; Cuming. 



The sculpture of this shell is very similar to that of the Arca bul- 

 lata ; it is, however, of much finer character, although the shell is 

 more elongated and altogether larger. 



Arca ocellata. Arca testd elongato-quadratd, lateribus superne 

 angulatis, latere antico brevissimo, infra rotundato, postico elon- 

 gate, infra acuminato, margine ventrali bi/sso latissi7ne hiante ; 

 albidd, epidermide tenui, subsetosd, indutd ; radiatim striatd, striis 

 subtilissime crenulatis ; mnbonibus remotis ; ligamenti ared latis- 

 simd, 7-hombo ligamentario pecuUariter ocellalo. 

 Conch. Icon. Arca, pi. 15. f. 102. 



Hab. Singapore (found in sandy mud at the depth of seven fa- 

 thoms) ; Cuming. 



This interesting little species exhibits a character which is quite 

 peculiar to the species. The dark ligamentary space between the 

 umbones is marked with a pair of oblique white oval spots, one on 

 each valve. 



Arca Donaciformis. Arca testd sub-Donacifoi-mi, medio leviter 

 coarctatd, latere antico brevissimo, truncate, postico elongato, sub- 

 acuminato ; albidd, epidermide vix nulla, striis transversis et Ion- 



