. Miscellanea , 315 



Amplexics arundinaceus (Lonsd.). 

 Common in the srray limestone of CurraduUa or Limestone Creek, 

 N. S. Wales. 



CRINOIDEA. 



Tribrachyocrinus (M'Coy), new genus. 

 Gen. Char. Cup o-lobose ; pelvis (or dorso-central plate) large, 

 saucer-shaped, pentagonal, tripartite ; first costals (or first row 

 of perisomic plates) five, one pentagonal, three hexagonal, and 

 one (?) heptagonal ; one of the hexagonal costfils is truncate above 

 and supports one pentagonal interscapular plate ; between these 

 and the heptagonal costal is situated one large, roundish, pen- 

 tagonal, intercostal plate ; in the re-entering angle between this 

 latter and the summit bf the heptagonal costal is an obscurely 

 hexagonal plate, analogous to a second costal. Scapulee (or ray- 

 bearing plates) three, rhomboidal or obscurely pentagonal, upper 

 margin rounded, lower margin j)ointed ; two of those in the 

 re-entering angles between the first costals and one in the. angle 

 between the intercostal plate and the second costal. Interscapu- 

 lar plates three, shield-shaped, pentagonal ; upper margin broad, 

 straight, truncate, with the two upper lateral angles horizontally 

 extended into short angular processes. 



The singular Crinoid for which I propose this genus is very 

 differently constructed from any other of the generic groups with 

 which I am acquainted. The cup is not symmetrical in form, like 

 that of other Crinoids, but is, as it were, humped on one side by the 

 interpolation of the large irregular intercostal (m.arked h in the 

 diagram) and the second costal (i). The only specimen found is 

 slightly crushed laterally, so as to render this inequality of the 

 sides very rerharkable. The arm-bearing plates or scapulae, which 

 are so generally five in the other genera, are only three in the 

 present animal, forming a strong peculiarity which it shares only 

 with the genus Triacrinus of Count Miinster (Beitrage zur Petre- 

 factenkunde), a little Crinoid of the Eifel difiFering in every other 

 respect from the Australian form. The general disposition of the 

 plates is most analogous to that of Poteriocrinus, from which it 

 differs in the number of the scapula and every point of detail. I 

 am as yet only acquainted with one species of the genus, which it 

 is not possible therefore to characterize specifically : I have dedicated 

 it to the Rev. W. B. Clarke, to whose zeal we owe the specimens 

 described in this paper. 



Tribrachyocrinus Clarkii (M'Coy). PI. XII. fig. 2. 



The surface is smooth, with the exception of a few irregular 

 radiating plicse at the margin of some of the plates, which seem in 

 some cases to overlap each other — an appearance, however, which 

 may be deceptive. Length of the cup 1 inch 7 lines, width about 

 IJ inch. 



From the soft gray shale of Darlington, N. S. Wales. 



Actinocrinus. 

 Fragments of pelvic plate of this genus occur in the Dunvegan 

 shale, and large columns apparently of Cyathocrinus are common in 



2c 



