284 THE FOSSIL ECHINOIDEA 



Phyllacanthid facies, in so far that they suggest the aspect of the spines of several of 

 the existing forms referred to that subgenus. The variety of the form of the spines in 

 the different living species of this subgenus, and the modifications both of shape and 

 character on different parts of the same test throughout the whole genus are so con- 

 siderable, that we consider it little more than frivolity and guess-work to assign specific 

 names to the detached spines with which we have now to deal. This opinion is 

 strengthened by the fact that we are quite unable to say which are the respective 

 spines belonging to the two species of Cidaris described on the preceding pages ; and 

 it is not a little remarkable that whilst tests of Cidaris were found at seven different 

 localities in the Gaj series, spines were found only at two of these (numbered by the 

 Survey G ^i^ and G ^i^, at which localities the denuded tests of C. opipara and 

 C. excelsa respectively were also obtained). Detached spines were met with at four 

 other localities, but no fragments even of tests were found associated with them. 



On Plate XLV we have given drawings of a representative series of the spines 

 from the Gaj strata : they are faithful delineations of the fossils ; and after the fore- 

 going remarks the following brief notes on their characters and occurrences will 

 probably be deemed sufficient : — 



Figs. 1-12 represent a series of spines which recall in the most vivid manner the 

 facies of spines of the type of the recent Phyllacanthus verticillata, Lamk. sp. The 

 shaft is thick and massive, ornamented with a coarse, widely spaced granulation, annuli 

 of larger and more prominent thorn-like granules being formed at intervals. These 

 characteristic transverse ridges are, however, confined to one side of the shaft, the 

 unarmed side, if it may be so termed, being occupied by regular longitudinal rows of 

 uniform small granules (see Fig. 3 a, which is the unarmed side of the same spine as 

 Fig. 3), often somewhat sharpened along their longitudinal axis and pointed outward; 

 and the general surface of the spine between the granulation is occupied by very 

 minute, uniform, microscopic granulation (see Fig. 12 a). Between the transverse 

 ridges the granulation is widely spaced and more or less irregular, except towards the 

 base (see Fig. 3 h). The basal articulatory portion of the shaft is small and contracts 

 rapidly, and the margin is smooth and not crenulated. At the distal extremity the 

 shaft is frequently flaring and cup-formed. Whether the spines represented by the series 

 of Figs. 1-12 all belong to the one species it would, in our opinion, be hazardous 

 to suggest. The spines of this type were procured at the following localities: — 

 i. Entering the hills on the road from Jangri to Bula Khan's Thana. Survey-number 

 G ^. ii. Sarochi, three miles north of Pokhan (collected by Earn Sing). Survey- 

 number G -3^. 



Fig. 13 is a large massive cylindrical spine of the character of the recent Phylla- 

 canthus imperialis and P. duUa ; it is marked with fine longitudinal striations, — the 

 edges of lamellae ; and the interspaces are filled in with a fine reticulated calcareous 

 network. The fossil is more tapered at the extremity than the spines of the recent 

 species we have mentioned, and the calcareous network between the lamellae appears 

 to be coarser. Furthermore the shaft does not expand as it approaches the collar, the 

 whole region of the collar being somewhat contracted in our form and of less diameter 



