32 PROCEEDINGS OF THE 



on April 24th. Contrary to the usual rule, this species seems 

 more abundant on the surface than deeper. 



Temora longicornis (Miill.) occurs the whole year round from 

 January to December, attains to high numbers in early spring, and 

 remains fairly abundant into late autumn. It reaches close on 

 7000 in one haul on April 1st, and 19,000 on April 9th ; and 

 shows 1280 and 1600 up to the 23rd of September. Temora 

 longicornis seems to be equally abundant inside the bay and in the 

 open sea, on the surface and in the deeper waters. Sometimes 

 the large numbers are in the surface-nets, and at other times in 

 the weighted net from below. This is one of the species that 

 congregates in swarms, and so is occasionally caught in unusually 

 large numbers. Of four similar hauls taken across Port Erin Bay 

 on April 13th, the first two gave 875 and 620 and the last two 

 1550 and 3700 specimens of Temora. On the same date three 

 hauls (two surface and oue deeper) taken outside (Station III) 

 gave 800, 850 and 900 specimens, which seems to indicate an even 

 distribution, but half an hour later a couple of miles away the 

 same two surface-nets gave 2400 and 4750 specimens ; and 

 moreover in this last case nearly all the Temora in the 2400 were 

 young, while in the second net the 4750 were all adults, indicating 

 a segregation of the stages in sAvarms. 



A set of hauls were taken at the end of August on Station V, 

 inside the Wart Bank. One remarkable feature of this occasion 

 was that the Hensen net hauled up from 14 fathoms contained 

 150 specimens of what is probably a new species of Leptopsyllus, 

 while the Nansen net used at the same time, and at the same 

 depth, on the other side of the ship, caught twice as much material 

 but not a single specimen of the new Copepod. The surface-nets 

 are also somewhat divergent in their results, while the deeper 

 weighted net has caught a very much larger quantity of material, 

 the greater part of which is clearly made up of Copepoda both 

 young and old — about ninety-five thousand in all. 



The two species of Cladocera found in our district, Podon inter- 

 medius and Evadne nordmanni, occur mainly in summer, in a wide 

 sense, ranging from the end of March to the beginning of October. 

 Our first record of Podon is six specimens on March 26th, and the 

 last is fifty on October 9th. Evadne begins with ten on March 

 29th, reached 500 on April 9th, and ends with 50 on September 

 20th. Tens, twenties and thirties are common numbers in the 

 records of both species, but sometimes the hundreds are reached. 

 As a rule there is no great difference between surface and deeper 

 hauls, and occasionally there is a great constancy of results, indi- 

 cating an even distribution : — e.g., on April 18th at Station II. 



At Station II. Surface-nets. 10 faths. Shear-net. 



Podon intermedins 150 150 — — 



Evadne nordmanni 100 100 150 50 50 



On April 19th, in the bay, two similar surface hauls took 40 

 and 37 Podon, and 75 Evadne each ; and at the same time, at 



