158 SPH^ROSYLLIS HYSTEIX. 



Proboscis with a tooth and with a series of papillae. The proventriculus is typical 

 of the family. 



De St. Joseph observes that the proboscis has lateral glands and a tooth in front. 

 The proventriculus has twelve rows of points. In the lateral pouches of the ventricle 

 is active ciliary circulation. 



In the foot (Plate LXX, fig. 1) the superior cirrus is small, much enlarged at the 

 base — especially anteriorly, and the posterior cirri longest. It is marked by minute 

 and scattered tubercles. The setigerous region presents long fleshy papillas, two of 

 which, near the apex, appeared to be regular in position — viz. one pointing forward and 

 the other backward. Each bears a number of jointed bristles (Plate LXXVIII, figs. 11 a 

 and 11 b), and the somewhat elongated terminal piece with a simple claw at the tip and 

 serrated along the anterior edge. In addition is a single simple bristle (figs. 12 and 13) 

 slightly curved towards the tip, and apparently dorsal in position. Then a tuft of 

 long simple bristles (swimming), stretching far beyond the body from the ninth segment 

 to the tail. In an example from the Minch no elongated swimming-bristles are present, 

 and the terminal pieces of the jointed bristles are somewhat longer. The ventral cirrus 

 is slender and short. 



De St. Joseph describes a rounded gland containing rods at the base of each foot 

 from the fifth to the last segment but one. 



Reproduction. — Professor Gr. S. Brady, who has for many years sent interesting 

 specimens, procured several pelagic examples in the tow-net off the coast of Co. Down. 

 All the females (Plate LXVI, fig. 3) carried eggs, but no example out of eight or ten had 

 swimming-bristles. On the other hand, the only two males bore swimming-bristles 

 (Plate LIX, fig. 4), and were distinguished in other respects from the females by the 

 smaller number of segments, which, moreover, were more deeply cut, so that the aspect 

 was moniliform. The long bristles commenced on the eleventh bristled foot and 

 continued to the posterior end, which, however, was incomplete. These pelagic forms 

 had the eyes considerably larger than the littoral. 



The females of these pelagic Syllids have a series of ova projecting freely from the 

 dorsum in some cases, and in others from the ventral surface, and apparently fixed to 

 dorsal or ventral cirri or between the feet, or to the feet by a tough thread. 



In an example of medium length they formed four irregular rows, occupying more 

 than the median third of the dorsum, about five bristled segments at each end being free. 

 By transmitted light the ova had a reddish speck (oleaginous ?), and readily became 

 detached during the manipulations. 



In a small female considerable elongation of the bristles was present, but no capillary 

 swimming-bristles could be distinguished. 



Habits.— So far as observed, these Syllideans frequent the under-surfaces of stones 

 near low-water mark, especially in their earlier stages, but when carrying ova in the one 

 case, or ripe sperms in the other, they appear to become pelagic. The great proportional 

 size of the ova would seem adverse to pelagic activity, but their specific gravity is 

 probably such as to aid the annelids in this nomad life, a supposition the more likely 

 as the majority of the females obtained had no swimming-bristles. 



