DOLIUM, 



Geuus DoLlUM, Lamarck. 

 Testa temm, glohoso-tumida , veiitricosissima, transversim 

 cosiaia, nimguam longitmUnaliter exsculpta, apertm'd 

 ampld, lahro simpUci, cretiato, raro fimhriato, labro 

 oolumellari late expanse. Operculum nullum. 

 Shell tliiu, globosely swollen, extremely ventricose, trans- 

 versely ribbed, never longitudinally sculptured, aper- 

 ture large, lip simple, crenated, rarely fimbriated, 

 columellar lip broadly expanded. No opercidum. 

 The DoUa or ' Tuns ' are mainly distinguished from 

 other genera of the great family of Purpurifera to which 

 they belong, by their large globosely inflated gi-owth, 

 transverse ribs, and absence of any sort of longitudinal 

 sculptiu-e, presenting a singular contrast in this respect 

 with their allies, the ' Harps,' in which ribs only occur in a 

 longitudinal direction. 



As may be gathered from the very Ught structure and 

 ample volution of the shcD, its animal inhabitant is dis- 

 tinguished for its large size and muscular strength, as well 

 as by its voracity and comparative activity of habit. The 

 head is furnished with a long retractile proboscis which 

 the animal is capable of rapidly protruding or withdi-awing, 

 fiu-nished at the extremity with a kind of rosette, as re- 

 presented in the beautiful figure of B.perdix in the Voyage 

 de I'Astrolabe by MM. Quoy and Gaimard. The disk or 

 foot of Dolium is large and fleshy and, according to M. 

 Deshayes, becomes inflated with water, when the animal 

 desires to swim, imbibing the fluid through certain pores 

 in the skin. The colours of the animal present a brilliant 

 contrast with those depicted in the shell ; the D. perdix is 

 striped with light azm-e blue, the D.ponmm is also light 

 blue, and the B. okarium is of a rich coppery green. 



The Bolia arc partially distributed, although the B.per- 

 dix occurs equally on the shores of the Philippine Islands 

 and in the West Indies. The B. pommii is found also 

 both iu the Philippine and Society Islands. This and 

 the B. rhiyeus from Peru are of more solid growth than 

 the rest, and peculiar in having a hollow excavated in the 

 columella, on which account they have been separated 



from tlie geuus Ijy M. A'alenciennes under the title of 

 Malea. The D. galea of the Mediterraneau is remarkable 

 for its lai-ge size, but the B. variegatum has been recently 

 collected at Torres Straits, North Australia, of even more 

 gigantic proportions. 



The shells of this geuus, though not much esteemed by 

 collectors, are by no means common ; only fourteen species 

 are known, and of these, but one new one has resulted 

 from the researches of Mr. Cuming or Sir E. Belcher. 



Species 1. (Mus. Cuming.) 



DoLlusi GALEA. Bol. testd max'mid, verdricosissimd, uid- 

 bilicaid, spird brevl, paululum subsidente, suturis pro- 

 fu7ide impressis, anfractibus septeni, superne tumidis, 

 fraiimersim costatk, costis convexis, confertk, superi- 

 oribus lira sapissime i?iterveniente, columella subcon- 

 tortd ; albidd ant palUde fulvd, apice nigricanie, lafiro 

 colnmellari albd, labro iiit.usfusco tincto. 



The helmet Tun. Shell very large, extremely ven- 

 tricose, urabilicated, spire short, a little sunk iu, 

 sutures deeply impressed, whorls seven in number, 

 swoUen round the upper part, transversely ribbed, 

 ribs convex, close-set, upper ones with most frequently 

 an intervening ridge, columella somewhat twisted; 

 whitish or pale fulvous colour, apex blackish, colu- 

 mellar lip white, lip stained within with brown. 



Lamakck, Anim. sans vert. (Deshayes' edit.) vol. x. p. 139. 

 Bucciuum galea, Linnseus. 

 An eadem var. ? 



Bolium ampuUaceiiM, Philippi. 

 Testa juvenis. 



Bntiiihi tenue, j\Ienke. 



Bab. Jlediten-anean. 



The above recorded synonymes of this well-known species 

 have arisen out of the circumstance of its having a more 

 oblong forn\ in an early stage of growth, and an occasional 

 1 irregularity in the tlevelopment of the ribs. 



Pecenilicr, 184S 



