MAEINE BIOLOGICAL STATION AT PORT ERIN. 



31 



and does not rise in any to 55 %. In round numbers 

 it may be said that in these examples the silica makes up 

 from 20 to 50 % and the calcium carbonate from 40 to 

 80 %. In all the neritic deposits there are in the residue 

 small quantities of calcium phosphate, of iron and of 

 alumina. 



In some of these deposits the calcareous matter is 

 formed almost entirely of Lithothamnion. Amongst the 

 Nullipores from our neritic deposits Professor Harvey 

 Gibson has identified the following species : — Lithotham- 

 nion polymorphum, L. calcareum, L. agariciforme, L. 

 fascicidatum, the variety fruticulosum, and Lithoplujllum 

 lenormandi. 



One of these neritic deposits (A) has its calcareous 

 matter formed by a large number of animals, belonging 

 to various groups, in addition to nullipores. One sample 

 (measuring 7 qts., 1^ pts., and weighing, when dry, 17 lbs. 

 3J ozs.) which I have gone over carefully for the purpose of 

 identifying the constituent particles contains more or less 

 fragmentary remains of at least the following 99 species, 

 all of them forms that leave calcareous remains : — 



Nullipores : 



LitJiotha mnion fascicidatum 

 L. calcareum 

 Lithoplujllum lenormandi 



ECHINODERMATA : 



Echinus splicer a 

 Echinocyamus pusillus 

 Echinocardium cordatum 



Vermes : 

 Serpida, sp. 

 Spirorbis, sp. 



Polyzoa : 1 



CeUaria fistulosa 



* New to district. 



Cellepora avicularis 



C. clichotoma 



C. pumicosa 



Idmonea serpens 



MicroporeUa ciliata 



M. malusii 



M. viola cea 



Schizotheca fissa 

 *S. divisa 



Mast ig op ho ra h ijndma nni 

 *M. dutertrci 



Mucronella peach ii 



M. variolosa 



t Identified by Miss L. R. Tliornely. 



