270 'Ringueberg on the Niagara Shales. 
has been found both singly and in groups at the only two ac- 
cessible exposures known ; and as it has been found nowhere 
else and seems to be the most constant form the band has been 
named after it. The fine almost black tracery of its columns 
is generally seen associated with few other fossils. Uemicysti- 
tiics parasiticus is another species which I have never found 
elsewhere. All specimens collected by me show them to be 
parasitic on Sfirifera niagarensis., but Prof. Hall mentions 
having secured it also on 6". radiatus. 
The specimens usually occur on individuals, in the colonies 
of the former species, and sometimes two may be seen side by 
side on the same valve. In this connection it may be mentioned 
that a peculiarity of iS"^/r//^/'a niagaretisis is that it is gregarious, 
living in small sized colonies so that the specimens at times al- 
most completely cover slabs of shales, with comparatively few 
individuals in the intervening spaces. 
This band has also yielded the only star fishes so far found, 
cy.ce'pi Pa hvastcr //iagarcnsis^the exact horizon of which is un- 
known, as Prof. Hall refers the single type specimen indef- 
initely to the shale at Lockport. These consist of eight indiv- 
iduals of Protaster stcllifcr and a type each of Eugaster con- 
cinnus and Squamaster echi)iat7is. 
Next to these the Lccauocriiii are the most characteristic group. 
The species of this genus are confined mostly to the lower 
third except L. macropciah/s which is found in the middle third. 
The rest range sparingly through the lower third and ter- 
minate here with many species and more individuals than in all 
the rest of the shale. A species which resembles P. calyctilus 
is the most abundant; the others are P. cxcavatus., P. macropct- 
ah/s.^ and P. nifidi/s. These except P. macropctalus seem to 
be peculiar to this band. P.solidus andP. putco/j/s are from the 
lowest band of the lower third. The fine state of preservation 
of many of the specimens occurring in this band and the layers 
immediately above and below it, is noteworthy. This is es- 
pecial) v true of species as a rule found onl}- in a disconnected con- 
dition. Qf these the well known Caryocriiius ornatus is the 
most prominent example. The portion of the shale within a 
few feet in cither direction from the Homocrinus band has 
yielded the most perfect specimens of this species which have 
