REPRODUCTION AND HABITS OF EOLIS. 511 



in March or April. The same specimen will some- 

 times spawn repeatedly at intervals, producing bun- 

 dles of ova resembling minute sausages, measuring 

 three lines in length, or less, and commonly found 

 attached to the stalks of Tubularia. 



Under favourable circumstances, the eggs may be 

 observed arranged singly, as if in long compartments, 

 across the mass; and when nearly mature, if exa- 

 mined under the microscope, will be found to contain 

 active beings, which, on escaping from their confine- 

 ment, prove to be Nautilines, resembling the progeny 

 of Doris, already described ; these immediately begin 

 to swim about with great vivacity, some individuals 

 pursuing their course singly through the water; or 

 several, clustering together, may be seen revolving 

 horizontally in merry dance, and forming a most 

 amusing and interesting scene. Nothing more, how- 

 ever, than what has already been recorded, relative 

 to the general* structure of Nautilines, distinguishes 

 these diminutive larvae. 



The Eolis dwells in society, and is rarely found 

 solitary. It is one of the few Nudibranchiates whose 

 food is known, which renders it a favourite subject 

 for observation ; and as the young grow readily, and 

 rather speedily, the progressive evolution of their 

 different organs may be satisfactorily investigated. 

 Still it must not be supposed that all the Eolides have 

 appetites precisely similar. The " Porcupine Eolis" 

 (Eolis hystrix), for example, shows several peculiar 

 propensities. It does not shun the light ; and, above 

 everything, its voracity, so different from the usual 

 habits of its race, is most remarkable. It feeds 



