AND THE FISH THEREOF. 15 



Echinodcrm Astcriscus ciliatus, Phasianclla pulla, Ceritkium vulg., Trochus 

 lhasoletti, and Cyclonassa nerithea, a curious little whelk resembling a nerithea 

 in shape, creeping on the sand and burrowing in it. 



In shallow and sheltered creeks, whose muddy bed is covered with 

 Valonia, is found a numerous variety of small Crustaceans, viz., Gammarus 

 sciss una 11 its, A mphitoe guttata, Cymodoce pilosa, Sp/ueroma yurinii. 



Loam or red clay bed is rare, and affords little attraction to animal or vege- 

 table life ; the characteristic species are Gcbia litoralis, Scobicularia piperita, 

 and species of Spheeroma and A mphitoe. This is a favourite site for the 

 propagation of the sand-smelt (At/ierina Jicpsetus) and various species of grey 

 mullet [Mugilidce) ; in the month of April the young fry is caught by the 

 million in the Bay of Dobrigno, and transferred to the lagoons of Venice and 

 the valli chiuse (fish-ponds), where they are reared as nourishment for other 

 fishes. 



On black muddy ground, composed of decaying animal and vegetable 

 matter, and in the shallows of sheltered bays, the characteristic Annellides are 

 Cirratiilus Lamarckii, not found elsewhere, also species of Clymene, Glycera 

 alba, hitherto known only in Norwegian and Danish waters ; the Mollusks 

 Ceritkium seabrum, Natica pulehella, Trochus canaliculatus, Venus nitcns, 

 V. Leta, Psammobia vespertina, &c, also prevail here. 



ZONE IV. — The Sub-Littoral Zone, extending from 2-10 fathoms; 

 average temperature 57 to 59° F., subject to slow changes; pressure at 

 6 fathoms 2' 13 atmospheres; the variations of the temperature are only 

 slightly less than those of the surface waters; effect of waves, slight. This 

 is the region of the sea-flags, or tangles, lying beyond the lowest ebb, which 

 are overgrown by dense Cystoseira. The number of Algae is very much 

 reduced, as also the prevalence of the different species, only forty-four species 

 belonging to eighteen genera being found here. On the sea-shrubs live a 

 quantity of Mollusks, Actiniae, and Ascidians. Characteristic are four Crusta- 

 ceans, one Annellide, ten Mollusks, two Echinoderms, one Polyp, and one 

 sponge. The latter is the Aplysina aerophoba, a remarkable yellow sponge 

 which grows on craggy rock-inclines, mostly covered by more, or less, dense 



