NORTHUMBERLAND AND DURHAM. 147 



oval holes. Most of the spicules have little "beads" or "knobs" 

 arranged round the perforations with some degree of regularity. 

 These beads do not, however, occur on all the spicules. I am 

 unable to state whether their presence is an indicator of age ; 

 possibly it is, as those without them are manifestly of more re- 

 cent production : figs. 22-25 appear to be the earlier stages, figs. 

 26-28 those of more mature growth. The largest examined 

 measured it&nr of an inch across, the largest perforations being 

 only toVd of an inch. Figs. 29 and 30 represent the spicules 

 found at the tips of the suckers : these are very small, being 

 only Trrb-tr of an inch across their widest part ; many of the per- 

 forations are only Tubus of an inch in diameter. 



Thyone flexus, Hodge. 



Thyone flexus, Hodge. Nat. Hist. Trans, of Northumber- 

 land and Durham, Vol. I. PI. X., figs. 2-13 (which 

 see for drawings). 



Rare, a single specimen from Berwick Bay. 



The only instance in which this species has occurred was in 

 1864, when a specimen was taken, as recorded above, in deep 

 water. Having so recently figured the spicules it is unnecessary 

 that they should appear here. 



Genus. PSOLUS, Oken. 



Psolus phantapus, Linn. Snail Sea-cucumber. PI. HI., figs. 

 1-21. 



Holothuria phantapus, Linnaeus. Syst., p. 1089. 



Psolus phantapus, Forbes. Hist. Brit. Starfishes (1841), 

 p. 203. 



Cuvieria phantapus, Diiben and Koren. Skan. Echi., 

 p. 313. PI. IV., fig. 34. 



Occasionally brought in by the five-men boats, rare by the 

 dredge. Young from Berwick Bay, G. H. Cullercoats, J. A. 



Only once taken in a mature state during the dredging expe- 

 ditions, viz., in 1862, on the Northumberland coast. It is 



