198 THE ATLANTIC. [chap. iv. 



in which the young are developed directly from the egg with- 

 out undergoing any metamorphosis, until they have attained 

 a diameter of about 2*5 mm. ; they are then entirely covered 

 with plates, and are provided with spines exceeding in length 

 the diameter of the test. Even before they have attained this 

 size and development, the more mature or more active of a 

 brood may be seen straying away beyond the limits of the 

 " nursery," and creeping, with the aid of their first few pairs of 

 tentacular feet, out upon the long spines of their mother. I 

 have frequently watched them return again after a short ram- 

 ble into the marsupium. 



I am not aware that a free pseudembryo, or " pluteus," has 

 been observed in any species of the restricted family Cidaridse ; 

 but I feel very certain that Cidaris jpapillata in the northern 

 hemisphere, except possibly in the extreme north, has no mar- 

 supial arrangement such as we find in the Kerguelen Cidaris. 

 There have passed through my hands during the last few years 

 hundreds of specimens of the normal northern form, of the 

 Mediterranean varieties C. hystrix and C. affinis (Stokesii), and 

 of the American C. abyssicola, from wide-spread localities and 

 of all ages ; and I have never found the young except singly, 

 and never in any way specially associated with breeding indi- 

 viduals. 



In Stanley Harbor we dredged many specimens of an irreg- 

 ular urchin, much resembling in general appearance Brisopsis 

 lyrifera^ the common "fiddle urchin" of the boreal province 

 of the British Seas, and probably to be referred to Ilemiaster 

 Philippii, Gkay. 



These urchins were not breeding when we were at the Falk- 

 lands ; but on the 9th of January, 1874, we dredged from the 

 pinnace in shallow water, varying from 20 to 50 fathoms, with 

 a muddy bottom, in Accessible Bay, Kerguelen Island, innumer- 

 able samples of apparently the same species. 



The test of a full-sized example (Fig. 43) is about 45 mm. in 



