533 



ENTOMOSTOMATA. 



ENTOMOSTOMATA. 



551 



Lamarck. M. De Ferussac divides the genus into two sub-genera, 

 namely, the Buccina properly so called, of which S. undatum may be 

 considered the type, and the Eburnce. 51. Sander Rang adopts his 

 arrangement. We confine ourselves to the true Buccina. 



Ex. B. undatum, the Common Whelk. This is the species so 

 commonly exposed for sale as food on the street stalls in the 

 metropolis. 



Shell of Common Whelk (Ducemum undatum}, and animal (male) creeping 

 with its shell and operculura. 



S. Lapilliu (Pa.rpv.ra.) is one of the English shells that product 

 the purple dye, analogous to the Purptira of the ancients ; and Mr. 

 William Cole, of Bristol, thus describes (1684) the process of obtaining 

 the English Purpura : " The shells being harder than most of othei 

 kinds are to be broken with a smart stroke with a hammer, on a plate 

 of iron or firm piece of timber (with their mouths downwards), so as 

 not to crush the body of the fish within ; the broken pieces being 

 picked off there will appear a white vein, lying transversely in a little 

 furrow or cleft next to the head of the fish, which must be digged 

 out with the stiff point of a horsehair pencil, being made short and 

 tapering. The letters, figures, or what else shall be made on the linen 

 (and perhaps silk too) will presently appear of a pleasant light green 

 colour, and if placed in the sun will change into the following colours, 

 that is, if in winter about noon ; if in the summer an hour or two after 

 sun-rising, and so much before setting ; for in the heat of the day in 

 Bummer the colours will come on so fast that the succession of eacl. 

 colour will scarcely be distinguished. Next to the first light green il 

 will appear of a deep green, and in a few minutes change into a sea 

 green ; after which, in a few minutes more, it will alter into a watchet 

 blue ; from that, in a little time more, it will be of a purplish-red : 

 after which, lying an hour or two (supposing the sun stUl shining), it 

 will be of a very deep purple-red, beyond which the sun can do no 

 more. But then the last and most beautiful colour, after washing in 

 scalding water and soap, will (the matter being again put into the sun 

 or wind to dry) be of a fair bright crimson, or near to the prince's 

 colour, which afterwards, notwithstanding there is no use of any 

 stiptic to bind the colour, will continue the same, if well ordered, as I 

 have found in handkerchiefs that have been washed more than forty 

 times ; only it will be somewhat allayed from what it was after the 

 first washing. While the cloth so writ upon lies in the sun it will 

 yield a very strong and foetid smell, as if garlic and asafwtida were 

 mixed together." (' Phil. Trans.,' Abr. II. 826.) 



Wu have inserted this account here, because the shell which is the 

 subject of it may be more familiar to our readers under the Linnseati 

 name of Buccinum Lapilltui than of Purpura, Lapillut, but it im- 

 properly arranged under the genus Purpura. 



fotril Baccina. M. Deshayes, in his Tables, makes the number of 

 fossil (tertiary) species 95, and he records the following as both living 

 and fossil (tertiary), Naita not appearing as a genus in his list S. 

 undatum, reticulatum, maculotum, mutubUe, clathratum, neriteum, 

 JJemoyerti, pritmaticum, atperulum, musinwn, injtatum, polyyonum, 

 1/Orkiynii, Linnaei, politum, and five new species, the names of which 

 are not given. Dr. Fitton notes two species below the Chalk, namely, 

 B. angulatum and B. nalicoide in the Portland Stone (North Wilts, 

 South Wilts, Bucks), and the last-named species in the Portland Sand 

 (Bucks). Dr. Lea rotes one species (new), B. Soweriii, iu the 



Claiborne Beds, Alabama. He observes that of the genus 27 species, 

 including Nassa, have been observed in Great Britain, several as low 

 as the Mountain Limestone, but chiefly in the London Clay and the 

 Crag. After repeating the number given by Deshayes, Dr. Lea says 

 that the genus appears to be much more abundant in the upper 

 formations. The Pliocene of the Sub-Apennines furnishes 27 species. 

 Bourdeaux (Miocene) 21 species. Paris (Eocene) 9 species. In 

 America, he adds, four species have been found, Mr. Say having 

 described two from the older Pliocene, Maryland, and Mr. Conrad two 

 from York Town, Virginia, also older Pliocene. The fossil species 

 now known, including those of Pwrpura, are about 150. 



Nassa. Animal very much depressed, with a very large foot 

 extending beyond the body on all sides, but especially in front, 

 where it is large and angular, whilst posteriorly it is insensibly 

 narrowed. For the rest like the animal of Purpura. Shell globular, 

 oval, or subturriculated ; aperture oblong, notched anteriorly ; right 

 lip sharp-edged, often plaited within ; columellar lip covered with a 

 large callous plate, extending more or less far. Operculum horny. 



Dr. Lea (' Contributions to Geology") says, "I have not hesitated to 

 separate this genus from Buccinum (although Lamarck united them 

 after having made the division), because they certainly form a very 

 natural group. Cuvier separates it, as De Blainville also does, into 

 a sub-genus." De Blainville certainly makes one of his sections of 

 Buccinum consist of the genus Nassa ; but Rang separates it decisively. 



The species of Nona, have a world-wide distribution, being found 

 in arctic, tropical, and antarctic seas. They have been found on 

 reefs, coral sand, sand, sandy-inud, and under stones, at depths 

 ranging from the surface to 15 fathoms. About 70 species are known. 

 N. reticulata is common on English shores, and called the Dog- 

 Whelk by fishermen. [NASSA.], 



Fossil Ntace. The species of Fossil Nassa: are above 20. They 

 are found in the Eocene Strata of Britain and North America. 



*** Ampullaceous Entomostomata, or those whose shells are in 

 general globular. 



Harpa. Animal with a large head, without a proboscis, having 

 the mouth opened below ; two anterior tentacula, conical, and 

 very much approximated, carrying the eyes upon an enlargement 

 situated externally a little below the middle ; foot large, furnished 

 anteriorly with a sort of heel; siphon rather large and a little 

 elongated ; branchial pectinations unequal, two in number ; orifice 

 of the oviduct at the entrance of the branchial cavity of the right 

 side, orifice in the deferent canal at the extremity of a very volumi- 

 nous excitatory organ ; vent on the same side. 



Shell oblong, more 01 less convex, generally rather delicate, 

 enamelled, furnished with regular longitudinal ribs ; spire a little 

 elevated and pointed, the last whorl very large; aperture oval, 

 elongated, widely notched anteriorly, the right lip with an external 

 bourrelet; columella simple, pointed anteriorly. No operculum, 

 according to M. Reynaud. 



Shell of Ifarpa teiitricota, and animal crawling with its shell. 

 The genus is found in the seas of warm climatep, and is more 

 especially abundant at the Mauritius and the neighbouring islands, 

 whence the finest of the more common species and the many-ribbed 

 Harps are procured. The animal is said to be of a rich vermilion 

 red. The fiphery is principally carried on at low water with a small 



