of the Fishery Board for Scotland. 



189 



The only points of interest in connection with the distribution of 

 Pseudocalanus elongatus, so far as can be made out from the tow-net 

 records of its occurrence, seem to be these — (1st) if an average of all the 

 records of this Copepod for the seven years be taken, the numbers for 

 April and May will be seen to be greater than those for all the other 

 months added together ; and (2nd) that the maxima of the records for 

 the seven years occur in 1891, 1892, and 1893. 



Anomalocera pater soni, which from its very large size and beautiful 

 colour is easily detected among the tow-net gatherings, is recorded a con- 

 siderable number of times during the seven years. The greatest total 

 number of records for any of the years is that for 1891, the number for 

 that year being nearly double that for any other of the whole seven, as 

 shown by the formula. 



Formula (1) shows the number of records of Anomalocera for each 

 of the seven years : — 



Numbers of the Years, - - - - 1889. 1890. 1891. 1892. 1893. 1894. 1895. 

 Total number of Records for each Year, 7 13 17 6 9 4 6 



This formula shows a gradual increase to the maximum, then a some- 

 what irregular decrease. 



Formula (2) shows the total number of records of Anomalocera for 

 each of the twelve months : — 



Names of the Months, Jan. Feb. Mar. April. May. June. July. Aug. Sept. Oct. Nov. Dec. 



Number of Records fori Q 003 20 18 871401 

 each Month, J 



It will be observed that by far the largest number of records for this 

 species occur in May and June ; they are much fewer in July, August, 

 and October, and rarely, or none at all, in the other months. It would 

 appear from this that Anomalocera is not resident in the estuary, but is 

 only a summer visitor, and, as Formula (1) shows, its visits are fairly 

 regular. 



Formula (3) shows the total number of records of Anomalocera for 

 each of the six stations : — 



Inner Stations. Outer Stations. 



Numbers of the Stations, - - - I. III. IV. V. VIII. IX. 



Number of Records for each Station, - 5 5 1 15 16 19 



The difference between the inner and the outer stations is very marked 

 here, but is only what might be looked for if Anomalocera be only a 

 " visitor " to the estuary and its vicinity. This also explains why 

 Station IV. appears to have been so rarely visited, for, being a migrant, 

 Anomalocera is more likely to keep as much as possible to the open 

 water, and avoid inshore localities. 



The distribution of the other species mentioned in the lists of tow-net 

 fauna does not call for special analysis ; but a few of them are of interest 

 because of their beauty, their rarity, or because of their structural 

 differences and habits. 



Metridia hibernica, which is of an elongate form, and has a long and 

 moderately slender abdomen, is recorded only once during the seven 

 years — viz., at Station IX. in May 1892, when a few specimens were 

 obtained. Metridia is a comparatively large Copepod. 



Candace pectinata is also moderately large, and is readily noticed by 

 its dark chocolate-coloured swimming feet. There are several records of 

 this species in the lists of tow-net invertebrates. 



Parapontella hrevicornis appears to be only once recorded for the seven 

 years, but the species is not very rare locally. 



