36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I28 



in their bodies. In three out of six females of this species taken on 

 January 27, 1950, oil droplets were conspicuous. Similarly, of three 

 females of Weyprechtia heuglini taken on June 23, 1950, the two larg- 

 est were developing marsupiums and their bodies were filled with oil. 

 This oil was undoubtedly being used in producing eggs that could be 

 laid when the marsupiums were fully developed. 



The shrimp Eiialus gaimardi was an excellent animal in which to 

 observe the storage of oil and its subsequent use. It was present in 

 practically every dredge haul and in sufficient numbers to lend value 

 to the observations made on it. Its integument is always more or less 

 transparent, but in the fall specimens of this shrimp were so filled with 

 stored food that they were quite opaque. From February until July 

 specimens were taken through the ice by means of screen traps. The 

 first specimens taken showed small ovaries in the process of develop- 

 ing. In specimens taken on subsequent months the ovaries were larger 

 and larger and the shrimps became more and more transparent as the 

 amount of stored oil diminished. By the end of June the ovaries were 

 filled with well-formed, distinct eggs and the bodies were so trans- 

 parent that there seemed to be nothing within them except the masses 

 of eggs. A soft-shelled female was taken on July 22, 1950, and on 

 August I, 1950, a total of 15 ovigerous females with eggs in very early 

 stages of development and another female that was obviously just 

 ready to lay its eggs were collected. 



An analysis of the oil content of various animals throughout the 

 year would undoubtedly reveal that the storage of oil is a common 

 practice and is developed to a high degree among Arctic marine 

 invertebrates. 



REPRODUCTION PHENOMENA 



Although years would be required to obtain a knowledge of the 

 methods of reproduction, the egg-laying season, and the size of the 

 eggs of the animals collected, a few facts became evident in the short 

 time devoted to this phase of the project. 



Perhaps the most noticeable of these reproductive phenomena is 

 the tendency among Arctic marine invertebrates to brood their eggs 

 or to provide some other method of protecting them until the embryos 

 develop either into large larvae or young animals similar to the adult. 

 Thorson (1936) has already observed the practice among Arctic 

 gastropods of laying eggs in capsules or in masses of jelly in which 

 the young develop either to the crawling stage or to a late embryonic 

 state with a shortened pelagic life, in marked contrast to the tendency 

 among temperate, equatorial, and tropical species to lay smaller eggs 



