Stages in the Life History of Ca/anus finmarchicus 
(Gunnerus), Experimentally Reared by Mr. L. R. 
Crawshay in the Plymouth Laboratory. 
By 
Marie V. Lebour, M.Sc., 
Assistant Lecturer in Zoology, Leeds University. 
Temporary Naturalist in the Plymouth Laboratory. 
With Plates 1 to 5 in the Text. 
[The stages in the development of Calanus finmarchicus described and 
figured by Miss Lebour in the present paper were taken from culture jars 
given into my charge by Mr. L. R. Crawshay, when he left the Laboratory 
to undertake military duties in connection with the war. In one jar at 
that time the first copepodid stage, from eggs laid in the jar, had just 
been reached, and the technical details for the successful rearing of the 
animals had been mastered. The experiments had been conducted with 
great care, and all possible precautions had been taken to prevent con- 
tamination. Subsequently the experiments were repeated up to a certain 
point by myself and some additional stages obtained to complete the 
series. 
The cultures were made in 2-litre glass beakers, containing “ outside ”’ 
sea-water filtered through a Berkefeld filter. In order to secure an even 
temperature the beakers stood in the circulating water of the Laboratory 
tanks, and a pure culture of the diatom Nitzschia closterium was used as 
food.—KE. J. ALLEN. | 
Aut the 5 copepodid stages (the 6th being the fully formed copepod) 
and 5 out of the 6 nauplius stages were found. Unfortunately the 6th 
nauplius stage was missed and could not be found in the material, but 
it is described and well figured by Grobben (1903), and his figures and 
description show that it is very like the same stage of Pseudocalanus 
and Paracalanus described by Oberg (1906). The latter author’s descrip- 
tions agree very closely with all the corresponding stages of Calanus 
jinmarchicus, the size in all cases being the chief difference. In the very 
NEW SERIES,—VOL. XI. NO. 1. MARCH, 1916. A 
