HARDWICKE'S SCIENCE-GOSSIP. 



103 



Great Explorers" series, and it will be a difficult 

 matter for any subsequent volume to excel it. The 

 story of the Palestine Exploration is one of the most 

 interesting on record, and Major Conder relates it 

 with the graphic skill of one who is a trained author 

 and an ardent explorer. There is not a dull page in 

 the book. It is full of realistic Oriental scenes and 

 settings, whilst the work of the expedition is detailed 

 in a manner which interests both Biblical students 

 and general readers alike. There are seven chapters, 

 devoted to the Explorations in Judea, the Survey of 

 Samaria, Researches in Galilee, the Survey »of Moab, 

 Explorations in Gilead, Northern: Syria, and one 

 devoted to the Results of the Expedition. The in- 

 troductory chapter relates the origin of the Expedi- 

 tion, and does generous justice to all those who have 

 been concerned in it besides the author. We 

 cordially commend this unusually pleasant book. 





DISTRIBUTION AND HABITS OF THE 

 BRITISH HYDROBI/E. 



By A. J. Jenkins. 



IN the "Journal of Conchology," for October 1SS9, 

 there is a very interesting article, entitled 

 "Notes on British Hydrobbe, with a description of a 

 supposed new species," by Edgar A. Smith, F.Z.S., 

 of the British Museum of Natural History. 



As there appear to be a great want of knowledge 

 existing respecting the Hydrobiae, perhaps a brief 

 description of the recognised British species, with 

 particulars of their distribution at home and on the 

 Continent, together with a few remarks concerning 

 the " supposed new species," may not be deemed out 

 of place, and may possibly help to stimulate concholo- 

 gists to more thoroughly study our various species 

 and their varieties. 



The interesting little molluscs belonging to this 

 genus are very small, and they somewhat resemble 

 the Rissose in external features, but differ from these 

 more marine animals, in generally inhabiting brackish, 

 and sometimes quite fresh water, as well as by the 

 absence of the opercular appendage, or caudal fila- 

 ment. They agree with the Rissoae in possessing a 

 horny operculum, and long slender tentacles, and they 

 have the muzzle-shaped head characteristic of the 

 Litorinidae. As some species inhabit estuaries within 

 reach of the tides, while others prefer brackish and 

 quite fresh water, they may be said to form a con- 

 necting link between the marine and freshwater 

 mollusca ; and, having regard to the freshwater con- 

 finement of some species, it would almost seem 

 desirable to withdraw them from our British marine 

 list, and include them amongst our freshwater shells. 

 That Dr. Jeffreys was at one time of this opinion is 

 manifest by his classing them in the family Paludinidae, 

 although he afterwards transferred them to the 

 Litorinidae, stating that, when he originally included 



them in the Paludinidae, he had " not sufficiently con- 

 sidered their systematic relations." That the Hydrobiae 

 have for many years been somewhat of a puzzle to 

 conchologists is clearly proved by the very dissimilar 

 genera in which they have been placed during the 

 past century ; during 'which period they have been 

 figured and described as Rissoa, Turbo, Litorina, 

 Cyclostoma, Paludina, Cingula, &c, until finally 

 Hartmann conferred upon them the present generic 

 name Hydrobia. 



Dr. J. Gwynne Jeffreys, in his splendid work 

 " British Conchology," has described but three species 

 of Hydrobia as being indigenous to the British Isles, 

 viz. : Hydrobia sitnilis (Draparnaud), H. vcntrosa 

 (Montagu), and H. ulva (Pennant). 



The first species is very local in distribution in our 

 own country, and is described by Jeffreys as being 

 restricted to ditches on the marshes bordering the 

 Thames from " Greenwich to below Woolwich." It 

 has evidently been exterminated in this locality, and 

 lias migrated lower down the river, where it seems to 

 be confined to very narrow limits. On the Continent, 

 according to Jeffreys, it enjoys a very wide range, 

 extending from " France south to Corsica," and in 

 the south of Portugal, in running water and marshes, 

 In France it inhabits quite fresh water. H. ventrosa 

 and H. ulva are very generally distributed around 

 the coasts of England and Wales ; the former species 

 has also been taken by Jeffreys at Lame Lough, 

 Ireland, and the latter from Loch Carron in Storna- 

 way, and in company with H. ventrosa from the 

 famous Arnold's Pond at Guernsey. On the Continent, 

 according to the same authority, H. ventrosa is found 

 " in similar situations along the sea-coasts of Sweden, 

 France, and Portugal, as well as in Algeria." A 

 variety of // ulva, rar. Barleei, is described as in- 

 habiting the Baltic. Of these species, H. ulva would 

 appear to be the most marine in its habits, being 

 always found within 'reach of the tides, frequenting 

 mud flats, and ooze sands in profusion. The shell, 

 which is long and tapering, is somewhat blunt at the 

 apex, with seven or eight whorls of a yellowish or 

 yellowish-brown colour. The animal is very sluggish 

 and timid. H. ventrosa and H. similis inhabit 

 brackish-water ditches, which are seldom, but occa- 

 sionally overflowed by the tide. They may be taken 

 together from their habitat on the Thames marshes. 

 The shell of H. ventrosa forms a lengthened cone, 

 with six or seven whorls, which are, as its specific 

 name signifies, ventricose, or swollen. The body- 

 whorl is less than half the height of the shell. The 

 animal, which is very timid and sluggish, has a 

 persistent habit of floating shell downwards upon the 

 surface of the water. The shell of H. similis is 

 shorter, and more oval in contour, with five or six 

 rounded but compressed whorls, and a much shorter 

 spire ; the body-whorl is very round and expanded, 

 and exceeds one-half the height of the shell. The 

 suture is very deep and channelled, and the umbilicus 



