Zoolog]\ 231 



Lough Neagh Pla>iaria lacfea, P. tot-va and Polycelis nigra 

 are abundant. 



Trematoda and Cestoda. — It is not necessary to 

 mention the particular s[)ecies observed by Thompson and 

 others in the district, as they include mostly forms common 

 all over the British Isles, but attention should be specially 

 drawn to a series of papers^ by the late Dr. Drummond, who 

 made a special study of the Cestode and other parasitic 

 worms found in fish, which he procured from the neighbour- 

 hood of Belfast. 



R. F. S. 



ECHINODERMA. 



This group contains the animals generally known as 

 feather- stars, star- fish, brittle-stars, sea-urchins, and sea- 

 cucumbers. The principal feature of the Echinoderma is 

 the deposition in the integument of a crystalline deposit 

 of carbonate of lime, which may be in the form of minute 

 spicules or plates which may sometimes form a more or less 

 continuous skeleton. Another feature is the radiate struc- 

 ture, at once recognised in the ordinary star-fish. 



These animals are usually marine in habit, but a few live 

 in brackish water. 



The Echinoderma are divided into seven classes, two of 

 which are extinct ; the remaining five — Crifioidea, feather- 

 stars ; Asteroidea, star-fish j Ophiuroidea, brittle-stars ; Echi- 

 ?ioidea, sea-urchins; Holothiii-ioidea, sea-cucumbers — are 

 represented on our shores. 



Crinoidea. — The Rosy Eeaiher-star (A)itedon bifida) is 

 generally distributed off the coast in deep water up to about 

 100 fathoms, appearing in some places in great abundance ; 

 and the rather doubtful species, A. Alil/eri, has been 

 recorded from Belfast. 



Asteroidea. — The common Star-fish (Asterias ruhens) 

 is generally distributed round the coast; the spiny A. g/aci- 

 aiis and the small form A. hispida have occasionally been 

 taken. Henricia sanguifiolenta and the Sun-stars, So/aster 

 papposa and S. endeca, are of frequent occurrence on oyster- 



ij L. Dkummo.nd.— Notices of Irish I-^ntozoa. Magazine 0/ Natural 

 History, vol. ii (N. S.), 1838. 



