338 



Dr. G. J. Hinde — On a Palceozoic Sj)onge. 



amongst the Zoophytes, though its true nature is still a matter of 

 much doubt." 



Being desirous of ascertaining the true character of Eophyton 

 explanation, I applied to Dr. Hicks, who very kindly at once for- 

 warded to me the original specimen, as well as two microscopic 

 sections which had been prepared from it, and these very distinctly 

 showed that Dr. Hicks was quite correct in his later comparison of 

 the fossil to the Pyritonema of M'Coy. I have also been enabled to 

 compare it with the type specimen of Hyalostelia (P.) fasciculus, M'Coy, 

 belonging to the Cambridge Woodwardian Museum, which was kindly 

 lent to me by Prof. T. McKenny Hughes, and also with examples of 

 the same species in the British Natural History Museum, the Jermyn 

 Street Museum, and others kindly forwarded to me by Mr. G. H. 

 Morton, F.G-.S., from Pont Ladies, Llandeilo. 



Dr. Hicks's specimen is shown on the fractured sui'face of a slab of 

 hard black shale, which, judging from the distorted forms of the 

 Brachiopods in it, must have been strongly compressed. It has the 

 appearance of an elongated, slightly convex band with delicate longi- 

 tudinal striae or ribs. The band, which is about 5'5 mm. in width 

 and 1*5 mm. in thickness, can be traced continuously in a nearly 

 straight direction throughout the slab ; in one place it is slightly bent 

 and traversed obliquely by an incomplete fracture, which was sup- 

 posed by Dr. Hicks to be a joint in the stem, but which pi'obably 

 arises from compression in the rock. The band, for some distance, 

 is enveloped by a thin coating of the shaly matrix, supposed to have 

 been a cortical tissue ; where this is absent, the constituent spicular 

 rods are clearly exposed. 



Fig. 1. Eophyton? explanation, Hicks = Hyalostelia fasciculus, M'Coy, sp. Trans- 

 verse section of the bundle of spicular rods. From Dr. Hicks's type -specimen. 

 ,, la. The same, showing longitudinal sections of some of the rods. 

 ,, 2. A siDgle spicular rod of Eyalonema mirabile, Gray. The figures are all 

 drawn to the same scale of eight diameters. 



The apparent band is, in fact, a bundle of solid, elongated, cylin- 

 drical spicular rods, disposed parallel to each other, and for the most 

 part in close contact, but without any organic connection with each 

 other. In some instances the rods are compressed together so as to 

 become partially flattened, but originally they appear to have been 

 circular in transverse section. The minute interspaces occasionally 

 intervening between the rods are filled by the rock-matrix, and there 



