l> H L A S. 



Species S3. (Fig. «, b.) 



Pholas cuNEiFORiiis. Pho. tcstd parrd, nineald, clatisd, 

 oblique canali scrrato didsd ; marijine ventrali 

 antko IcKvigato, rotundato, latere dorsali costis 

 longitiidinalibus, arcuatis, serratis rugato ; poslice 

 concentrice striatd, plus miiuisve attemiata ; scutis 

 marginalibus tribns, lino ad margincm ventralem 

 elongate, uno ad margiiiem dorsalem angustisdmo, 

 una super mnbones disposito lata, aiitire obtusd 

 angulato, postice acuminato. 



The wedge-shaped Pholas. Shell small, cuneate, 

 closed, obliquely divided by a serrated canal ; 

 anterior ventral margin smooth, round, dorsal sido 

 roughened with longitudinal arched, serrated 

 ribs ; posteriorly concentrically striated, more or 

 less attenuated ; marginal shields three, one 

 elongated, on the ventral margin ; one very 

 narrow, on the dorsal margin, one broad, placed 

 upon the umboes, anteriorly obtusely angular, 

 posteriorly acuminated. 



Say. Journ. Sci. Philad., vol. ii. p. ;;22. 



Uab. N. America. 



The umbonal shield, instead of being broad and 



large as in Pholas striata, is narrow and lozeuge-shaped, 



more acute posteriorly than anteriorly. 



Species 34. (Mus. Cuming in Brit.) 



Pholas aperta. Pho. testd globosd, apertd, in iiiiilio 

 canali serrato divisA ; antice ad margiiiem ventralem 

 Bubangulafd ; costis laqueatis concentricis ornatd ; 

 postice Icevigatd, subattenuatd ; lamiiiis dorsalibus 

 quatuor, parvis, super umhones dispositis. 



The open Pholas. Shell globose, open, divided in the 

 middle by a serrated canal ; anteriorly rather 

 angular at the ventral margin ; ornamented with 

 concentric fluted ribs; smooth posteriorly, sub- 

 attenuated ; dorsal plates four, small, placed upon 

 the umboes. 



SowERBV. Proc. Zool. Soc., 1849. 



Hah. Straits of Suiula and Banca. 



Burrowing in floating mahogany, the shell of this 

 species has a reddish tint. The dividing groove is 

 nearer the anterior than the posterior end, while in 

 Pholas terediiiceformis the contrary is the case. It has 

 two pairs of dorsal plates, while the last mentioned 

 species has but one. 



Species 3.'.. (Fig. a, h, Mus. Brit.) 



Pholas obtecta. Pho. testd ovafd, suhpi/riioi-ini, rl,iti.sd, 

 canali medio divisd ; parte antii-<'i hitm- ilmvaJi 

 minute striatd, latere ventrali lau-i, mtmi'lo ; jiartc 

 posticd la-i'i, marginibus nnlni/ihii^ ili>rsali7>ii.<ijiii 

 taminis elongatis nbtectis, ad tirmiinim aiii/iisli.<. in 

 livninas artindalas <:i/,illi;j\,i„i, .< pi;„l,irtd ; scuta 

 dorsali iiinr/,i,,, ad iiiuh.aics hllohal,,, autice versus 

 uiargineiii riutniliui lati , rjiaiisn. 



Tni: SHELTEiiED Pudi.AS. Sh. II uvate, subpyriform, 

 closed, divided in t\v mi. Idle liy a canal, anterior 

 part minutely striated at the dorsal side; posterior 

 part smooth, rounded ; dorsal and ventral margins 

 covered with long plates, narrow at the end, pro- 

 duced into cyathiform articulated lamina; dorsal 

 shield large, bilobed at the umboes, anteriorly 

 widely expanded towards the ventral margin. 



SowEP.BY. Proc. Zool. Soc, 1849. Thesaurus Con- 

 chyliorum,Monog. PhoIas,No. 10, pi. 108, f. 80, 81. 



pfab. North Coast of Australia. 



J. E. Doring, Esq., R.N., collected this interesting 



species at Turtle Island in coral rock at low water. 



Sjiecies ^.M^. (Fig. a, h, Mus. Ciuning in Brit.) 



Pholas teredinjefok.mis. Pho. testd globosd, apertd, in 

 medio per canalem serralum divisd ; antice ad 

 margiiiem ventralem subaiigulatd, costis laqueatis 

 concentricis ornatd ; postice brevi, Icevigatd ; lumind 

 dorsali und. suhquadratd, super marginem rejiexam, 

 valcaruiii disjiositd. 



August, 1872. 



