P II L A S. 



Species 25. (JIus. Cum. in Brit.) 



Pholas cl.\usa. Pho. testd suhovatd, ventrimsu, clatisd, 

 omnino striis radiatu el costis moniUjormUms con- 

 ceiitiicis ornatd ; margine dorsali pnstice sujjlato, 

 antic'e valid'e expanse et sufflato, ad umbones traiis- 

 ven^e indso, snjier /(tiiiinas transfer sas triijonas 

 decumhenle ; ml tirminuin posticiciu subatteiiutitd, 

 epidermiih' ni'jricantr, /abis (juatuor injlatis, time 

 intcgumento ci/dtlii/ormi, /.fjiHiiso, ad la/era <:iaar- 

 ginaio. 



The enclosed Piiolas. Shell subovatc, voiitricusc, 

 ornamented in every part with nuliated stria: 

 and moniliforra concentric rilis; dors<vl margin 

 swelled posteriorly, much expanded and .swelled 

 anteriorly, transversely incised at the, nmboes, and 

 lying upon transverse trigonal plates ; attenuated 

 at the posterior end with a blackish epidermis, 

 with four inflated lobes, then a cyathiibrm, ex- 

 panded integument emarginated at the sides. 



Gray, in Brit. Mus. 



Pliolas explanata, Spengler. 



Uab. Kiver Gambia. 



By a strange moditic-itinn of the cu]) eharaeter, 

 Pholas clausa has a sort of fup-sh.'ipcd apiienJaae, so 

 divided as to appear like a pair of liaps. 



Species 26. (Fig. a, b, Mus. Cum. in Brit.) 

 Pholas quadra. Pho. testd oUomjo-subovatd., chiiisd, 

 medio canali serrato divisd ; parte anticd aistntd et 

 striaid, margine ventrali injkito, cum margine dorsa/i 

 confluenti, margine dorsali (umido, diriso, ad urn- 

 hones transverse inciso ; parte postird concentricc 

 striatd, in tumulis itijlatis qiiatuor, et tuba testaced 

 terminanti. 

 The square Pholas. Shell oblong-subovate, closed, 

 divided in the middle by a serrated canal ; an- 

 terior part ribbed and striated; ventral margin 

 inflated, confluent with the dorsal margin ; dorsal 

 margin tumid, divided ; transversely incised at the 



umboes ; posterior part (•(ineeiitrically striated, 

 terminating in four iiillateil swellings, and in a 

 testaceous tube. 



So\vi;i;i!Y. Proc. Zool. Soc, 1834. 



Ilab. Monte Christo. 



Not terminating in a half membranaceous eu{i as in 



Pholas papyracea, but in fimr horny swellings ^ur- 



mounting a shelly tube. 



Species 27. (Fig. a, b, Mus. Brit. 

 Pholas couticakia. Pho. lesld parvd, chii 

 constrictd ; anticd angiilatim longitmliii 

 tatd, costis serratis, margine reiitraii 

 postice prop!: iiiedium couceiitricc ylrint'K 

 plus iJiiNiisrr nil, iiiKitii : .■iciitib/is trihi 

 1llia eliingiilit ml iiKirgi m m riiitr^i/nii, in 



uiubones dispv.^itif. 

 :eI) Pholas. Shell small, el 

 the middh., angularly hni 

 ribbed in front, ribs serrated, veiitr 

 smooth, povtrriorly near the middii 

 trically siii.it. d, i xnvmity more or less a 

 shields thr.'c, of which one is elongated 



super manji 

 dnila, super 



■ieted 



uedin 

 slrictd, antice ad ninrgiiicin rentruletit lujhiUt : 

 dorsali piarvo, lutu, margine dursah pc.-liri 

 ticeque subexpanso. 



