276 Dr. W. C. Mcintosh oti the Boring of certain Annelids. 



Hyalothrix, Gray, P. Z. S. 1867, p. 119. 



Bark smooth. Polypes oblong when contracted, low. Ten- 

 tacles 40. 



Hyalothrix lusitanica^ Grray, I. c. 1867, p. 119. B.M. 



Type Hyalonema lusitaniciim, Bocage, P. Z. S. 1864, p. 265, t. 22 ; 1865, 

 p. 662 ; Gray, Ann. & Mag. Nat. Hist. 1866, xvii. p. 287; Lov6n, Ann. 

 & Mag. N. H. 1868, p. 90. 



Var. spongifera. 



H. lusitanicum, Bocage, Ann. & Mag. Nat. Hist. 1868, ii. p. 36; Bow- 

 erbank, P. Z. S. 1867, p. 902. 



Hah. Portugal. 



P.S. Dr. Perceval Wright, who has just returned from 

 dredging for Hyahnemata on the coast of Portugal, informs me 

 (Sept. 14) that he believes the coral {H. lusitanicum) grows at 

 the bottom of the sea in deep water, with the free part of the 

 coil sunk in the sand. He also mentioned to me that M. Bo- 

 cage has some specimens of the sponge that grows on the H. 

 lusitanicum with a shallow cavity that is covered with a netted 

 lid formed of spicules, like the lid of Euplectella. I do not 

 find any trace of such a lid in the three sponges on the Hyalo- 

 nema Sieholdii in the British Museum ; but it seems to exist 

 in some specimens of that sponge, as Dr. Loven says that Prof. 

 Schultze found " the flattened surface of the smaller and 

 younger specimen (No. 4) covered by a network of spicules 

 similar to that which covers the free end of Euplectella.^^ 

 (Ann. & Mag. N. H. 1868, ii. p. 89.) 



XXXIII. — On the Boring of certai7i Annelids. 

 By W. C. MCINTOSH, M.D., F.L.S.* 



[Plates XVin., XIX., XX.] 



At the Meeting of the British Association held at Dundee, 

 my friend Mr. E. Ray Lankester read a very interesting paper 

 on " Lithodomous Annelids," or, rather, on the boring of 

 Sabella saxicava^ Quatref., and Leucodore ciliata^ Johnst., 

 chiefly with reference to the latter. In the discussion which 

 followed, Mr. Gwyn Jeffreys and I strongly opposed the 

 theory advocated by the author as to the action of a purely 

 chemical agency in the production of the perforations. I spe- 

 cially mentioned that Leucodore ciliata bores in aluminous 

 shale — a fact fatal to the chemical (or acid) theory — and am 



* Communicated by the Author, having been read at the Meeting of 

 the British Association at Norwicli, Aug. 24, 1868. 



