THE EUROPEAN SEAS. 



185 



TerebratulcB increase, in addition to those of the 

 higher zones. T. truncata and T. cuneata appear, 

 with Crania. 



The Seventh Region, ranging from eighty to 

 a hundred and five fathoms, has characteristic 

 features. Herbaceous Fuci have disappeared, and 

 Nullipores are the only plants. The Tunicated 

 Mollusks have ceased, as also have Nudibranchiata. 

 Of Testacea, Lima elongata, Cardita aculeata, Rissoa 

 reticulata, and Fusus muricatus, are most generally 

 distributed, and the same JRissoa, with Turbo 

 sanguineus, Venus ovata, Nucula striata, Pecten 

 similis, together with the Brachiopods, which abound 

 here, are the most prolific. Echinoderms are not 

 uncommon, such as Echinus monilis, Gidaris hystrix, 

 Echinocyamus pusillus, and some Ophiuridce, but no 

 Asteriadce. 



The Bivalves of this zone are under thirty, with 

 about nine at their maximum. The Univalves are 

 about forty, with sixteen at their maximum. In 

 addition to all the fore-cited Terebralidw, are T. 

 lunifera, T. vitrea, and T. appressa. 



The Eighth and lowest region includes all depths 

 below a hundred and five fathoms. Over this sea- 

 bed, which consists of a fine yellow sedimentary 

 mud, full of the remains of Pteropods and Fora- 

 minifers (an unknown region till the researches 

 of Ed. Forbes and his associates in the Beacon), 

 there is found a uniform fauna distinguished from 

 all preceding regions by peculiar species. As would 



