marine biological station at port erin. 19 



Diatoms. 



Coscinocliscus and Biddulphia were very 



abundant in the collections taken in April and 

 the early part of May, 1903. These forms 

 gradually decreased and finally disappeared 

 towards the end of June. By the middle of 

 October both genera had reappeared, and con- 

 tinned to increase in quantity; the maximum 

 point in 1904 was reached early in March ; none 

 were observed after June 22. On September 

 27th, 1904, Coscinodiscus had just made its 

 appearance again. Chcetoceros was observed 

 once in 1903 (September 28). In 1904 it was 

 noted in the collections taken in January, 

 February, March, April, and first half of May. 

 Xone were seen again till September 27, when 

 it was again very abundant. 



Rhizosolenia was only noted once during 

 the whole period covered by the 39 tow-nettings 

 (May 11th, 1904). 



The gelatinous algse which frequently 

 chokes up the tow-nets in the summer months, 

 appeared in Port Erin on May 26th, 1903, and 

 remained till July 9th. During 1904 this 

 alga only occurred on May 4th and 11th 

 although it was very abundant oft' the Welsh 

 and Lancashire coasts during June and July. 



5. Protozoa. 



Representatives of this group occurred 



very sparingly, and the only forms noted were 

 Ceratium fusus, March 2, 1904, and Ceratium 

 tripos, November 7, 1903, September 10th 

 and 27th, 1904. A species of Acanthometra 

 was very frequent in the tow-nettings taken on 



