366 Mr. H. J. Carter on the Hexactinellidge. 



leads me to the conclusion that it must have belonged to a 

 specimen of Euplectella cucumer. That described by Professor 

 Owen and Dr. Farre I have never seen ; but no one can have 

 compared the specimens of Euplectella aspergillum, which are 

 very common now, with the figures of Euplectella cucumer 

 drawn on stone by that accurate artist Mr. G. B. Sowerby 

 (I. c), and those taken from photographs of Habrodictyon 

 specie-sum and H. corbicula obtained by Prof. Wy ville Thomson 

 (I. c), without being convinced that E. aspergillum, E. cucumer, 

 and Habrodictyon, if not distinct species, are very different 

 forms of the same type. 



Since writing the above I have carefully examined the spe- 

 cimen of Euplectella cucumer described by Prof. Owen, still in 

 the possession of Dr. A. Farre, F.R.S., whose kindness on the 

 occasion can only be exceeded by his continued desire for the 

 further elucidation of this beautiful species. I have also ex- 

 amined the figure of Alcyoncellum speciosum (Habrodictyon, 

 Wy. Thomson) given by Quoy and Gaimard in the Atlas to 

 their Natural History of the Voyage of the /Astrolabe ' in 

 1826-29 (pi. xxvi. fig. 3, Zoophytes, 1833); and, through 

 the kindness of my friend Dr. J. E. Gray, I am in possession 

 of excellent photographs of this and A. corbicula , Val., of the 

 natural size ; so that, with specimens of my own of Euplec- 

 tella aspergillum, I am altogether now able to state with 

 certainty the principal differences that exist between these 

 species. 



1st. Euplectella aspergillum has its spicular basketwork, 

 both of the body and lid, throughout cemented together by an 

 envelope of vitreous ladder-like fibre, which " ladder-like 

 fibre " in a horny state is also a peculiarity of some of the 

 kerataceous sponges. The main lines of spicules are longitu- 

 dinal and transverse, so that, cutting each other at right angles 

 and at nearly equal distances, they leave a number of squarish 

 areas in the intervals, occupied alternately by round holes and 

 matted basketwork. Through this arrangement, the squares 

 with holes and basketwork respectively form diagonal lines 

 again crossing each other, but now obliquely and somewhat 

 spirally round the body ; while a number of compressed 

 ridges or frills about a quarter of an inch high, and formed of 

 the same kind of vitreous spicular structure as the rest of the 

 sponge, run along in more or less continuous spiral lines ob- 

 liquely through the squares of matted basketwork, leaving 

 those with holes free between them, finally terminating 

 above in one which encircles the lid-like end where the 

 latter is joined to the body. The lower end, on the other 

 hand, which is also closed but of a conical form, similar to the 



