PELAGIC FAUNA. 41 



feature. Agaiu, the terminal portion of the intestine in the 

 larval herrings captured in March shows a deep greenish 

 coloration, which may be connected with chlorophyll, the green 

 colouring matter of plants. Moreover, even so minute a pelagic 

 form as an Infusorian is occasionally, as for instance by the 

 sardines, swallowed in masses as food. 



There is no more interesting part of the inquiry than the 

 gradual advent in the early part of the year of the larval fishes, 

 and their great abundance in the spring months, such as March, 

 April and May. Then, while the larval stages of a few still 

 appear in the warmer months, viz. June, July, and August, the 

 predominance of post-larval and young stages are the main 

 features. These become rarer in the pelagic fauna as winter 

 approaches, and finally almost cease to occur in the nets pro- 

 bably in many cases as much from their increased power and 

 activity as from their scarcity. 



In the same way the larval stages of mussels and other 

 shell-fishes of importance make their appearance at a stated 

 period, continue in great profusion for some time, and then 

 gradually diminish and disappear. In the case of the mussel 

 the advent of the larval forms in swarms is in touch with the 

 previously ripe condition of the adults on the beds, the long- 

 continued presence of certain of these Iarva3 being connected 

 with the later maturation of the reproductive organs in the 

 littoral and often stunted examples so abundant in many 

 parts, especially on the margins of rocks. 



Besides the special interest of the pelagic fauna in con- 

 nection with the fisheries, the bearing of many of the facts, e.g. 

 the appearance and disappearance of multitudes of swimming 

 jelly-fishes, is of a novel kind, since even the most recent 

 and most authoritative investigators of the subject, such as 

 Prof. Haeckel, do not exhaust the question. Little indeed has 

 been done in this respect since the days of Edward Forbes, 

 with the exception of the Notes made at the Naples Zoological 

 station, and those at the Plymouth Laboratory. 



The pelagic fauna round the British shores seems to have 

 many features in common, but the presence of the phos- 

 phorescent Noctiluca in the south, of the large Arachnactis in 



