154 Part III. — Sixteenth Annual Report 



six of them have been fixed upon as representative of the others — namely, 

 Stations I., III., IV., V., VIII., and IX. Stations I. and III. extend 

 from the east side of Inchkeith eastward, and are comparatively near to 

 each other. Station IV. is an inshore station, and extends for a consider- 

 able .distance round the u South Bay." Station V. extends from May 

 Island westward along the centre of the Firth till nearly abreast of Elie. 

 Stations VIII. and IX. are beyond May Island, and outside the limits 

 of the estuary. 



The results obtained by the use of the tow-nets were at first recorded in 

 a somewhat general form, but as the work proceeded the differentiation 

 of the various organisms became less difficult, and made it possible for a 

 more detailed description of the results being placed on record. It will 

 be obvious, therefore, that in the study of the distribution of the pelagic 

 invertebrates the earlier records will not be so useful as those of subse- 

 quent date. Moreover, the investigations were not carried on during the 

 first year or two so continuously as they were afterwards, and for these 

 reasons I propose to limit the consideration of the pelagic invertebrates to 

 those collected (by means of the surface and bottom tow-nets already 

 described) during the seven years from 1889 to 1895 inclusive, and 

 recorded in the several Annual .Reports for these years. 



But though the examination of the pelagic invertebrates within the 

 area under consideration was carried on more or less continuously and 

 regularly during the years referred to, there are times when, for various 

 reasons, no tow-net gatherings were collected, and for which there are no 

 records, so that the records for some years are less complete than for 

 others. In 1889, for example, there are no records of tow-net gatherings for 

 any of the stations in March, April, and December; in 1890, in January 

 and June ; in 1892, in August ; in 1894, in March, May, July, Sep- 

 tember, and October; and in 1895, in March, June, and November. 

 Moreover, there may be records for a particular month for some of these 

 stations and not for others. Thus in 1889 though there are records for 

 October for Station I. there are none for any of the other stations ; but 

 while that is so there are still a large number of statistics available for at 

 least a partial study of the distribution of the pelagic invertebrates of the 

 Firth of Forth. 



The time available for the preparation of this paper did not permit of 

 the detailed consideration of every species or kind of invertebrate re- 

 corded in the lists of tow-net gatherings, so that only those that are of 

 numerical importance, or that are otherwise of importance from a fisheries' 

 point of view, are so dealt with, while an endeavour is also made to 

 invite attention to any interesting point observed in connection with the 

 distribution of the other species. Tables illustrating in time and space 

 the distribution of these pelagic forms are introduced wherever they are 

 considered necessary. 



Moreover, four charts are added at the end of the paper for the pur- 

 pose of supplementing and extending the information given in the Tables 

 concerning the distribution of a few of the more, numerically or other- 

 wise, important species or groups of invertebrates comprised in the tow- 

 net lists. These charts not only show when and where the species was 

 abundant, or scarce, or absent, but they also allow of a comparison being 

 made between the surface and bottom distribution of the species. The 

 importance of this will be evident when it is remembered that though a 

 species may be rare at the surface it may at the same time be common or 

 even abundant at the bottom, as well as vice versa. 



It may further be stated that in proceeding to consider the distribution 

 of the invertebrates mentioned in the various lists of tow-net gatherings 



