DESCRIPTION'S OF THE SPKOIKs. 270 



examples of the type which have now conic to hand through the efforts of Mr. 

 James Bennie have enabled us to determine its generic affinities. By means 

 of careful manipulation we have succeeded in exposing hydrospire-slits on the 

 sloping sides of the radial sinuses, the presence of which indicates that tin- 

 species should be referred to our genus PhcBnoschisma. There are four slits on each 

 side of a sinus, which are particularly well marked for so small an organism (PI. II. 

 fig. 37), and two of them appear to be covered when the side plates of the ambulacra 

 are in place. This interesting type is so essentially distinct from all the other 

 species of Phamoschisma which are known to us, that we need not make any com- 

 parisons between them. 



The probability of its being an undescribed species was pointed out by one of us some 

 years ago ; and it now affords us much pleasure to name it after Mr. Bennie, to whom 

 British Palaeontology is indebted for several curious and interesting discoveries. 



Localities and Horizon. East Salton and Kidlaw Quarries, near Gilford, Hadding- 

 tonshire : Shale above the No. 2 Limestone, Lower Carboniferous Limestone Group. 

 (Presented by Dr. P. H. Carpenter, F.R.S.) 



"We have mentioned above that this is the ouly regular Blastoid which has yet 

 been found in the Carboniferous Limestone Series of Scotland. But the same shales 

 which have yielded both this type and Astrocrinus Bcnniei have been found by 

 Mr. Bennie to contain fragments of ambulacra, which we cannot recognize as belong- 

 ing to either species, and are not improbably those of Mesoblastus, Schizoblastus, or 

 one of the Granatohlastidce. They have been already described by one of us 1 , and 

 the figures then given are here reproduced (PI. II. figs. 38-42). 



(ii) Subfamily C R Y ft o sc H I sm I D je, E. & C, 1886. 



Definition. Ten groups of hydrospire-slits, few or none of which appear at the 

 sides of the ambulacra. Deltoids small and external or limited to the summit. 



Remarks. The two genera of which this subfamily consists are altogether unlike 

 each other, but each of them is closely related to Phamoschisma, having, like that 

 genus, the usual ten groups of hydrospires. The distinguishing character of Crypto- 

 schisma is the entire concealment of the hydrospire-slits, which are in all respects 

 like those of the Pluenoschismida?, by the wide and petaloid ambulacra (PI. V. 

 figs. 23, 24 ; PL XIII. fig. 20). But this condition is nearly reached, both in 

 Pirn noschisma caryopkyllatum and in P. acutum (PI. XIV. figs. 3, 4, 11). In fact 

 one interradius in our best specimen of the latter type is altogether in the condition 

 of Cryptoschisma ; and if all its side plates were preserved the summit would be 

 extremely similar to that of the latter genus (PI. V. fig. 23; PI. XIV. fig. 11), 

 though the general outline of the calyx is altogether different in the two types 



' Proc. Nat. Hist. Soc. Glasgow, 1881, vol. iv. p. 202, PI. Y. figs. 8-12 ; Geol. Mag. 1S78, vol. v. p. 118; 



