248 



HARDWICKE'S SCIENCE-GOSSIP. 



the value, or even the bearing of the illustrations 

 furnished by the authors. I have said before that 

 the processes — fertile or sterile — Palaeocorynse, are 

 unique in character and type, and it is only folly 

 to seek for similar processes in any of the modern 

 species of Polyzoa. 



In these papers I have endeavoured to give illus- 

 trations only of specimens of polyzonal processes from 

 my own cabinet, or from specimens that have 

 actually passed through my hands ; but as I have 

 been supplied with sketches of processes from the 

 cabinets of others, I could not resist the temptation 



Fig. 181.— Spiniferous processes of Fenestella plebeia (M'Coy) 

 fc Halkyn, North Wales ; a\ Basal origin of spine a 1 ; a 3 . 

 \ Fenestrules of the polyzoary ; bb. Imperfect fenestrules ; 

 c. The way the spines rose up in the undisturbed shale. 



of reproducing some, kindly furnished by Mr. John 

 Young. Fig. 46 (Science-Gossip, March 1879), is a 

 sketch of a branching spiniferous process in situ, on 

 a frond of Fenestella from Cragenglen Campsie. It 

 is four times the natural size, and it is one of the 

 most beautiful processes from the poriferous face 

 that I have ever seen. In Mr. Shrubsole's collection 

 there is another fine specimen of spiniferous process 

 springing from the back of the frond, altogether 



different from the one here figured. The specimen 

 from which fig. 181 is given, is a perfect study of this 

 particular process. It is from the Halkyn series of 

 Fenestella, and the drawing is made from a section 

 of the shale only partially rendered transparent. 

 The figure represents the outer portion of the frond 

 of F. plebeia, and the spiniferous processes are unlike 

 any of those given by the Messrs. Young. The 

 branch (a) originates in the dissepiment marked a x in 

 the fig. 181. It passes on then to a dissepiment 

 higher up, then into another, until it reaches the 

 outer branch, the continuation of which is spiniferous 

 until it reaches the extremity shown in my section. 

 Mark the character of this branch. There are regular 

 dissepiments part of the way up until at last the two 

 branches coalesce, and continue then, apparently, as 

 one solid spine. The two lower spiniferous branches 





Fig. 184. 



Fig. 183. 



Spiniferous processes. 



Fig. 185. — Palceocoryne radiata. 



are of a different character to the others. I have 

 given all that my section now shows. Before I rubbed 

 it down these branches were prolonged consider- 

 ably, not on the same plane as the part that is 

 shown in the fig. 181, but they penetrated through 

 the shale something like what is shown at (c), and 

 they bent from the poriferous face upwards. At 

 (bb) two partially developed fenestrules are shown. 

 I cannot trace any remains of zocecia in these 

 branches and there is no hollowness. The character 

 is that of a solid spiniferous shoot. The figs. 182 and 

 183 are from specimens from Richmond, and fig. 184 

 is enlarged to show the special character of the hook. 

 There is a specific value belonging to these spines, 

 which in all future diagnoses of species will have to 



