Mr Leslie on a Speeimen of Euplectella Asjpergillum. 77 



ing account of Euplectella* in which he describes the means 

 employed by the natives for its capture, and their manner 

 of preparing its skeleton. He states that it is to be found 

 only within a very limited area, and at a depth of 120 to 

 140 fathoms. It is known, however, that it has a rather 

 greater bathymetrical range than this, as shown by the " Chal- 

 lenger " specimens. Captain Chinimo figures two abnormal 

 forms, neither of which resembles that now exhibited, in 

 which one tube is a diverticulum of the other, both of his 

 specimens being double tubes, with equivalent longitudinal 

 axes. 



Eitplectella belongs to the family Hexactinellida, which is 

 characterised by its members always possessing six-rayed 

 siliceous spicules. The skeleton consists of a cylindrical 

 tube closed at its upper and lower extremities. The internal 

 cavity is simple, and is often inhabited by commensal crusta- 

 ceans. The average length of specimens, exclusive of the basal 

 fibres, is from eight to twelve inches, but some which have 

 attained the length of two feet are recorded. The normal form 

 which I now exhibit, and on which I shall base my descrip- 

 tion, is 24 centimetres = 9^ inches, in length. Its transverse 

 diameter at the apex is three centimetres, and this remains 

 almost uniform throughout the upper half of the sponge, but 

 it rapidly diminishes in the lower half, so that the transverse 

 diameter of the basal extremity is rather less than two centi- 

 metres. The lower third of the cylinder is sharply bent, and 

 this curvature also affects, but to a much less degree, the 

 upper part. A concave and a convex side are thus deter- 

 mined. In some specimens a secondary curve is seen near 

 the upper end, so that the side which is strongly convex 

 below, becomes slightly concave above. 



The parietes of the sponge are formed by white glistening 

 siliceous fibres, which are arranged in a very definite manner, 

 there being a transverse, a longitudinal, and an oblique set. 

 The transverse fibres are internal, and form annuli, which are 

 very marked when we examine the internal cavity. Each 

 annulus is composed of a considerable number of parallel 

 siliceous fibrils. They form a very regular series for the 

 * ^' 1^2ii\xxdiX History oi Eupleddla aspergillum.^' London, 1878. 



