MACTRA. 



Plate VII. 



Species 25. (Mus. Cuming). 



Mactra stJBROSTRATA. Mact. testd ohlongo-transversd, 

 tumidd, inaquilaleraU, striis transversis Uueiaque ra- 

 diantibm subtilibus impressis decussatd, ftdco-grhed ; 

 uvihonihus violaceis ; latere antico rotnndalo, podico 

 subrostrato, Jdante ; lunula plaidusculd, area lanceo- 

 latd, excavaid. 



The SLIGHTLY-BEAKED Mactra. Shell oblong-traus- 

 verse, swollen, inequilateral, decussated with trans- 

 verse striffi and fine depressed radiating lines, fulvous 

 grey; umboes violet; anterior side rounded, posterior 

 slightly beaked, gaping ; lunule rather flat, area lan- 

 ceolate, excavated. 



Deshayes, Pro. Zool. Soc. 1854. 



llab. Moluccas. 



Very closely allied to M. violacea, but more oblong and 



swollen, and slight!}' beaked at the posterior extremity. 



Species 36. (Mus. Cuming.) 



Mactra plicataria. Mact. testd transverse siibtriyond, 

 compreasd, ineequilaterali, concentrke irregulariter sub- 

 fiexuose plicato-costatd, oblique ndnntissime striata, 

 pellncido-albd, diaplmnd, epidermide tenni fused versus 

 margmem indutd ; latere antico subproducto, roiun- 

 data, posiico angulaio, plicato-carinato ; lunula lanceo- 

 lato-ovatd, area perampld, ambabus Icevibus ; imibonibiis 

 parvis. 



The plaited Mactra. Shell transversely subtriangular, 

 compressed, inequilateral, concentrically plieately rib- 

 bed, obliquely very minutely striated, transparent 

 white, diaplianous, covered towards the margin with 

 a thin brown epidermis; anterior side rather produced, 

 rounded, posterior angulated, plieately keeled ; lunule 

 lauceolately ovate, area very large, both smooth ; 

 umboes small. 



LiNNiEUs, Syst. Nat. (12th edit.) p. 1125. 



Hab. Island of Sumatra. 



This fine species is strongly plait-ribbed throughout, 



the plaits and interstices being very minutely obliquely 



striated across. 



Species 27. (Mus. Cuming.) 

 Mactra l.evis. Mact. testd ovato-triangidari, ineeqwi- 



laterali, caudidissimd, nitente, irregulariter ira?isrer- 

 sini minutissime striata, ad umbones plicatd, antice 

 posticeque late plicatd, in medio lavigatd ; latere antico 

 subproducto, rotimdato, postico truncato, plicato-angu- 

 lato ; lunula lanceolato-ovatd, area perampld, exca- 

 vaid, ambabus Icevibus ; sinu pallii brevissimd, apice 

 obtuso, oblique triangulari. 



The smooth Mactra. Shell ovately triangular, inequila- 

 teral, very white, shining, irregularly transversely very 

 minutely striated, plaited at the umboes, broadly 

 plaited anteriorly and posteriorly, smooth in the 

 middle ; antei'ior side rather produced, rounded, pos- 

 terior truncated, plieately angled ; lunule lauceolately 

 ovate, area very large, excavated, both smooth ; sinus 

 of the mantle very short, obtuse at the top, ob- 

 liquely triangular. 



Chemnitz, Conch. Cab. vol. vi. p. 211.. pi. 21. f 305 

 and 20r5. 



Mactra striatula, pars, Gmelin. 

 Mactra subpUcata, Lamarck. 

 Mactra Spengleri, Born (not of Liunasiis). 



ffab. Island of Samar, Philippines ; Cuming. 



Distinguished by a faint row of ripple-like plaits de- 

 scending on each side the umboes. 



Species 28. (Mus. Cumiug.) 



Mactra hians. Mact. testd oblongo-ovatd, subtrigond, 

 tenulculd, ineequilaterali, transversim dense minute 

 striatd, livido-albd, fulco-rufo radiatd, ad umbones 

 violaceo iinctd ; latere antico subtruncato, postico lon- 

 giore, rotimdato, Jdaide ; lunula lanceolaio-ovatd, ared 

 angustd, Icviter rugoso-angnlatd. 



The gaping Mactra. Shell oblong-ovate, subtriangular, 

 rather thin, inequilateral, transversely densely mi- 

 nutely striated, livid white, rayed with fulvous-red, 

 violet-tinged at the umboes ; anterior side subtrun- 

 cated, posterior longer, rounded, gaping ; lunule lau- 

 ceolately ovate, area narrow, slightly rugosely angled. 



Philippi, Abbild. und Beseh. Conch. Mactra, pi. 3. f. 1. 



Eab. Island of Mindanao, Philippines ; Cuming. 



A fine ruddy-rayed species, of rather thinnish substance, 

 gaping at the posterior end. 



April, 1854. 



