220 ATTTOLYTUS PROLIFER. 



evidently feeding, and the alimentary canal is distended. May 11th, 1887. — The yonng 

 are now pale greenish, with eyes of a lnstrons silvery bine. 



The male buds (Polybostrichus, Plate L, fig. 11) occur from February onward to 

 November, and probably throughout the entire year, and are discriminated by their 

 shorter bodies and structural differences. 



Head comparatively small, with two circular dark brown eyes (in spirit), reddish 

 or blackish in life, which have a lens and which look laterally as well as dorsally, a 

 long median tentacle arising behind them, and a large and long pair of cirri laterally (post 

 cephalic). From the front of the head project the bifid palpi, which are undivided and 

 massive at the base. The outer division is short, the inner long, tapering, and often 

 thrown into graceful coils. These processes appear to develop considerably after the 

 separation of the bud from the nurse- stock — just as the body increases in length and bulk. 

 A smaller and more slender cirrus is ventral to the great tentacular cirrus, and a still 

 smaller to the outer side of the eye. 



On the ventral aspect of the head a large pair of eyes occupies each lateral region, 

 and each also shows a cuticular thickening or lens. These eyes chiefly look downward, 

 though in a lateral view of the head a considerable portion of the pigment. of both dorsal 

 and ventral pairs is visible. 



Body increasing in length, and probably in the number of its segments, with age; 

 slightly narrowed in front and tapering to a slender tail. A median furrow runs along 

 the dorsal surface, while ventrally the nerve-cord and the adjoining ventral longitudinal 

 muscles form three central stripes. Behind the head are fourteen narrow segments 

 provided with slender dorsal cirri, which are largest in front, and the ordinary bristles 

 with bifid terminal pieces. 



In the next region the feet project more, so that the body is broader, and the 

 dorsum of each has a tuft of the long swimming-bristles. These are longest in the 

 anterior twelve or fourteen segments and diminish gradually in the succeeding. The 

 feet so provided were twenty-eight in number in a fine example fully half an inch in 

 length. In these the dorsal cirrus is shorter than in the anterior region. Each foot 

 has also beneath the former a group of the ordinary bristles with the bifid terminal 

 pieces. About thirty diminishing segments with short dorsal cirri, and the ordinary 

 bristles with the bifid terminal piece, occur posteriorly, the last having two larger cirri, 

 though they are not conspicuous. The peculiarly broad and flattened body of this form, 

 and its long bristles, fit it, like the young Nerine, for example, for its pelagic life. The 

 specimen from which the foregoing description was drawn up was captured on February 

 1st. Most of those procured in the subsequent months were smaller. 



The stolons have neither proboscis nor proventriculus. They swim gracefully and 

 vigorously, the sheen of the long lustrous bristles with their ever-changing hues being 

 very beautiful. 



De St. Joseph gives an account of the changes in the muscular system in the second 

 region of this form (male). 



Martin Slabber (1778) describes and figures under the name of Scolopendrina marina 

 (Zeedurzendbeen) a female bud of this form, with swimming-bristles, in which the larvaa 



