AND THE FISH THEREOF. 17 



Cymodoce pilosa, C. tnuica/a, Sphceroma Jurinii, Pectinaria auricoma, 

 Nereis zostericola, and Buccinum ascanias do not descend below 6 fathoms. 



The pipe, or needle-fishes {Syngnathidce), the gar-pike {Be lone vulgaris), 

 and the wrasse {Labrus turdus) are also found here. 



Squilla mantis, Maja squinado, Murex brandaris, Pecten jacobceus, and 

 Ostrea edulis are forms which abound in this region, in the Gulfs of Trieste 

 and of Venice. They are exceptional in the Ouarnero, var. cristata being 

 the only kind of oyster found in some parts of this gulf. 



ZONE V. — This is the medium declivity and depth extending from 

 10 to 20 fathoms, mostly on steep inclines, rarely on flat beds. 



Sweet surface waters have no effect here, and submarine springs do not 

 issue forth in this region; specific gravity of water 1,027; intensity of the 

 effect of the daylight on the decrease, rays of light yellowish and difference 

 between night and day perceptible ; pressure at 15 fathoms 3^67 atmospheres ; 

 no effect felt of the action of the waves ; no drift currents, but the chief 

 currents reach to the bottom of this zone ; average temperature 56 F., 

 difference of temperature between summer and winter, 18-20 F. 



This zone corresponds closely with Professor Forbes' Laminarian Zone. 

 The number of Alga^ falls off considerably, particularly the typical forms of 

 the Mediterranean and Adriatic flora, general forms only remaining. The 

 lower declivity and the flat bed are both characterised by dense and high 

 Cystoscira and Nullipores, which especially abound there ; few Diatomacece 

 remain. Characteristic forms : — eight Crustaceans, four Annellides, twenty- 

 two Mollusks, eight Echinoderms, two Polyps, and two Sponges. 



On bare rocks, free of, or with little vegetation, in crevices and fissures 

 are found the Conger-eel (Conger vulgaris), the common lobster, the crabs 

 Palinurus vulg., and the smaller Pratiiza ccvrulata ; in sponges, Typton 

 spou^ieula and the Echinoderm Ophiopsila aranea of Forbes. The Annellides 

 Serpula contortuplicata and Terebella parviloba adhere to stones. Eunice 

 norvegica, E. galliea, Meckelia an unlaid, and Polyuo'e cirrata, a Boreal and 

 Celtic Annellide, where it attains to higher development than here, are often 

 found in the holes of stones, or amongst the coral-like Nullipores. 



o 



