REPORT ON A COLLECTION OF ANTARCTIC PLANKTON. 293 



many of these pelagic organisms pass most of their lives 

 in water of a temperature below 32° F., and it would be 

 most interesting to learn more about their reproduction 

 and general life-history. 



''In the Southern and Sub-antarctic Ocean a large 

 population of the Echinoderms develop their young after 

 a fashion which precludes the possibility of a pelagic 

 larval stage. The young are reared within or upon the 

 body of the parent, and have a kind of commensal con- 

 nection with her till they are large enough to take care 

 of themselves. A similar method of direct development 

 has been observed in eight or nine species of Echinoderms 

 from the cold waters of the northern hemisphere. On 

 the other hand, in temperate and tropical regions the 

 development of a free-sw r imming larva is so entirely the 

 rule that it is usually described as the normal habit of the 

 Echinodermata. This similarity in the mode of develop- 

 ment between Arctic and Antarctic Echinoderms (and 

 the contrast to what takes place in the tropics) holds 

 good also in other classes of Invertebrates, and probably 

 accounts for the absence of free - swimming larvae of 

 benthonic animals in the surface gatherings in Arctic 

 and Antarctic waters." 



Of the Copepoda obtained, curiously enough the com- 

 monest species is apparently new to science. It agrees 

 generally with Scott's genus Paracartia, in which I have 

 placed it as Paracartia antarctica, n. sp. It occurred in 

 eighteen of the gatherings. 



The well-known Calanus Jinmarckicus, so commonly 

 distributed throughout our northern latitudes, appears to. 

 be equally common about the Antarctic, and occurred in 

 sixteen of the gatherings. 



Associated with C. ftnmarchicus, and fairly plentiful in 

 some of the bottles, was the large red Arctic species 



