202 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



to the increase in one species of Copepod — Oithona similii. 



August 14th showed an unusually large number of 

 Copepod Nauplii and of Oihopleura. 



66.— Port Erin Bay. August 14, 15th, 16th, 17th. 



Depth in Fathoms 



Catch' in com 18 18-5 17-5 30*5 



Ceratium tripos 1,000 1,000 500 — 



Pleurobrachia pileus — 1 3 



Medusoid gonophores 250 2 100 



Sagitta bipunctata 600 1,800 800 700 



Tomopteris onisciformis — 25 6 



"Mitraria" 100 — — — 



Crab zoea 200 300 — 5 



,, megalopa — 3 — 20 



Mysis stage of Crangon 200 200 2 15 



Podon intermedium 300 — 100 200 



Evadne nordmanni 100 — — — 



Calanus helgolandicus 50 700 500 700 



Pseudocalanus elongatus 3,500 700 500 800 



Temora longicornis 3,500 6,500 2,500 2,000 



Centropages hamatus 100 200 200 200 



Acartia clausi 1,000 600 100 200 



Oithona similis 12,000 6,000 5,000 25,000 



Caligns rapax — — 1 — 



Paracalan ns parvus 250 — — — 



Copepod nauplii 25,000 13,000 3,500 13,000 



,, juv 4,000 4,000 3,500 5,000 



Lamellibranchs, larval 1,500 — — — 



Oikopleura sp 2,800 900 200 200 



Fish eggs, Rockling 15 1 40 25 



Brill — — — 1 



,, Goldsinny — 1 — — 



111 Form 104 we show an example of the Diatom 

 fauna that makes its appearance again late in September. 

 The two surface nets represented show very large numbers 

 of Diatoms, extending up to 13 millions and 16 millions 

 in single hauls in the case of Rhizosolenia semispina — in 

 fact this highest peak in the September maximum of 

 Diatoms is mainly composed of this one species of 

 Rhizosolenia, whereas in the spring maximum the bulk 

 of the catch, as may be seen from Form 10 (p. 200), is 

 made up of Chaetoceros contortum and Thalassiosira 



