276 Prooeedings of the Boyal Physical Society. 



Thelepus circinatits (Fab.). 



Firtli of Forth, 30 fatlioms; Bass Eock, 

 24 fathoms {Moh). 



Sabellid^. 

 Sabella ]jctvonina (Sav.). 



Very common on the oyster bank, and in 

 deeper water; also in sand at Aberdour 

 at very low water. 



SEKPULIDiE. 



Serpula vermicidaris (Linn.). 



Common, off Inchkeith, 5 fathoms, etc. 



(noh.). 

 Spirorbis horealU (Davd.). 



Very plentiful on Algas at low water. 

 S. lucidus (Mont.). 



On Hydroids, etc., in all parts of the 



estuary. 



PYCNOGONIDA. 



This group has been recently separated from the Crustacea 

 and Arachnida, with which it was formerly associated, and 

 arranged as an independent class of the Arthropoda. 



Nymphonid^. 

 Nymphon gracile (Leach). 



Not uncommon among stones and weeds 

 between tide marks, and we have dredged 

 it off May Island, 14 fathoms ; Kirkcaldy 

 Bay, 6 fathoms ; off Inchkeith, 5 fathoms ; 

 and in many other parts of the estuary. 



Phoxichilid^. 

 Pycnogonum litoralc (0. F. Miill.). 



Common between tide marks, but also 

 found in deep water. We have dredged 

 it in 18 fathoms. We found specimens 

 near Inchcolm, at the end of April of this 

 year, having large masses of ova attached 

 to them. 



