47 72 Proceedings of the Royal Irish Academy. 



Habitat. — Mature male dredged in 15-16 fathoms near Bonn Harbour 

 in June. Dredged in large numbers in Clew Bay, in 24 

 fathoms on a bottom of sand and shells. 



Distribution.— Dinard ; Madeira; Mediterranean (Saint-Baphael). 



Mystides (Mesomystides) linibata de Saint-Joseph. 

 PI. VIII, fig. 18 A, B. 



1S88. Mystides (Mesomystides) limbata. De St. -Joseph, p. 310. 



This species was dredged in Inishlyre Harbour and in Clew Bay. It is 

 at once distinguished by the fan-shaped array of spines at the end of the 

 shaft of the seta (fig. 18 b). Another distinguishing character is the winged 

 expansion of the ventral tentacular cirrus on the second segment, though 

 this character is much more obvious in living than in preserved specimens. 

 The typical foot (fig. 18 A) has oval dorsal and ventral cirri and a bifid 

 setigerous lobe with 6-9 setae. The latter are curved, and the tip of the 

 shaft bears a single strong tooth with a fan-shaped series of spines on each 

 side. The terminal blade is coarsely serrate and obliquely striated. The 

 anal segment bears a pair of fusiform cirri. The proboscis has nine papillae 

 at the tip, and is covered with large conical papillae. 



De Saint- Joseph states that both mature males and females are provided 

 with capillary swimming bristles, and this adaptation seems to be character- 

 istic of all members of this genus. I have found a mature female with 

 capillary setae in Galway Bay. Its proboscis was extended, and terminated 

 in a ring of about 10 papillae. It had 44 segments, and capillary setae from 

 the 14th to the 30th segment. De Saint-Joseph's specimens had 93 segments 

 and capillary setae from the 35th to the 85th segment. 



Habited. — Clew Bay — Dredged in 24 fathoms, on a bottom of sand and 

 shells. Also in Inishlyre Harbour, in 2-4 fins., on a bottom 

 of Lithothamnion. 



Distribution.— -France (Dinard, Brest). 



Mystides (Mesomystides) borealis Theel. 



PI. VIII, figs. 19 A-D. 



1879. Mystides borealis. Theel, p. 35, IT. II, figs. 29-32. 1879 A. Mystides 

 caeca. Langerhans, p. 310, Taf. XVI, fig. 42. 1887. Mystides viridis. 



Webster & Benedict, p. 712, figs. 10-12. 1913. M. c. Fauvel, p. 53. 



A single specimen of this species was found, together with a lai'ge number 

 of other remarkable Polychaetes, in Clew Bay, in 24 fathoms (Station W. 84). 

 I have since found two others on similar ground outside Dingle Bay, in 78 



