ON THE ZOOLOGy OF THE SANDWICH ISLANDS. 353 



mittee available for this purpose will be exhausted. He has been working 

 almost solely on the island of Oahu, where zoological devastation is taking 

 place both extensively and rapidly. 



Seven parts of the ' Fauna Hawaiiensis ' have now been published, 

 and two more are in the press. The part published since the last 

 report is devoted to Coleoptera, and was prepared by Mr. Perkins while 

 in this country, and by the Secretary of the Committee. 



It is hoped that Mr. Perkins' services may be secured after his return 

 to this country with the object of completing the ' Fauna Hawaiiensis.' 



The Committee asks for reappointment with the same powers as 

 before and a grant of 50/. 



PlanJclon and Physical Conditions of the English Channel, 1899-1900. — 

 Interim Beporl of the Committee, consisting of Professor E. Ray 

 Lankester {Chairman), Mr. W. Garstang (Secretary), Professor 

 W. A. Herdman, and Mr. H. N. Dickson. {Brawn %ip hy the 

 Secretary.) 



Thk analysis of the numerous collections of Plankton made during the 

 periodic cruises in 1899-1900 is now approaching completion. 



Owing to the many disadvantages of the counting method introduced 

 by Hensen an attempt has been made to utilise the method of graded 

 tiltration in the quantitative analysis of the vertical hauls, the mass of 

 each ' grade ' being determined volur^trically. Five grades have been 

 selected, which correspond in general with the following dominant types 

 of the plankton : — (1) Medusoids, (2) Calanus, (3) small Copepods, 

 (4) Larvae, (5) Diatoms and Cilioflagellates. The largest grade is that 

 determined by a square mesh whose side is 1'5 mm. long ; the next by a 

 mesh I mm. square. These dimensions are approximately realised in 

 bolting silk ('miller's gauze') having sixteen and twenty-six threads to 

 the inch respectively. The following table gives the complete aeries of 

 standard filters adopted : — 



It is found that the errors which attend the volumetric method when 

 applied to plankton samples consisting of mixed and varied constituents 

 are greatly reduced by the preliminary process of separation into definite 

 grades of size ; and it is hoped that a thorough trial of this method of 

 analysis may result in its establishment as an eificient method for the 

 quantitative comparison of plankton of different localities and seasons, in 

 conjunction with the method of vertical hauls introduced by Hensen. 



The Committee respectfully request their I'eappointnient for one year 

 longer, without a grant, in order that they may present a summary of the 

 results to the next Meeting of the Association. 



'o 



1901. A a 



