150 



velfulvo-zonatd ; spird conicd, acuta ; anfractibus 6, planiusculis, 

 suturd profundd junctis, ultimo convexiofe, vix descendente ; colu- 

 mclld brevissimd, basi denticulatd, callum emittente tenuem, vix 

 circumscriptum ; aperturd pariim obliqud, semiovali; peristomate 

 acuto, subrecto. Operculum tenue, testaceum, carneum, margine 

 columellari elevato. 



Diam. maj. 6^, min. of, alt. 5 mill. 



Hah. St. Domingo (SallS). 



3. Contributions towards a Monograph of the Tro- 



CIIID^, A FAMILY OF GaSTEROPODOUS MoLLUSCA. 



By Arthur Adams, R.N., F.L.S. etc. 



Genus I. Trochus, Linn. — Pyramiclea, sp. Swains. 



1. Trochus niloticus, Linn. 



Trochus Jiiloticus, Linn. ; Gmel. p. 3565. no. 1 ; Chemn. Conch, v. 

 t.l67. f.lG05, t.l68.f.I614. — Trochus marmoratus,Lamk. (young). 

 Hub. North Australia {Drinff). 



2. Trochus maximus, Koch. 



Trochus wMxhrnis, Koch ; Phil. Abbild. Trochus, t. 6. f. 3. 

 Hub. ? 



3. Trochus acutangulus, Chemn. 



Trochus acutangulus, Chemn. Conch, v. t. 1G3. — Trochus conus, 

 Gmel. 



Hub. Burias. 



4. Trochus spinosus, Lamk. 



Trochus spinosus, Lamk. Hist. An. s. Vert. t. vii. p. . 

 Hab. ? 



5. Trochus asperulus, Lamk. 



Trochus asperulus, Lamk. Hist. An. s. Vert. t. vii. p. 22. 

 Hab. ? 



6. Trochus Cumingii, A. Adams. T. testd turrito-conicd, vio- 

 laced, maculis viridibus pulcherrimh pictd ; anfractibus planis, 

 cinyulis, granorum moniliformibus ornatis, infernh nodoso-pli- 

 catis, anfractu ultimo angulato; peripherid radiatim nodo-spi- 

 nosd, basi concavd, cingulis granulosis, insculptd, centra pro- 

 fundi excavato umbilicum simulante ; columelld superne tor- 



tuosd, basi dente terminatd ; aperturd tetragond ; labro intus 

 lirato. 

 Hab. Sibonga, island of Zebu, under stones at low water {H. C). 

 Mus. Cuming. 



7. Trochus fastigiatus, A. Adams. T. testd conicd, imper- 

 foratd, rubrd, maculis albis longitudinalibus variegatd ; an- 



