436 DR. P. II. CARPENTER ON 



number of the arms broke at one of the lower syzygies, and the great beauty of a large 

 and perfect Crinoid was irretrievably ruined. 



The third species herein described, Metacrinus Stewarti, is unfortunately only repre- 

 sented by a stem fragment ; but its characters are so different from those of the stem in 

 any species of Metacrinus yet known to me, that I have no hesitation in regarding it as 

 belonging to a new specific type. 



Although Mr. Stewart had long since commenced to write an account of the fine 

 specimen in his hands, and had also made a few drawings of it, his usual unselfish kind- 

 ness has led him more than once to offer it to me for description ; and when I received 

 Dr. Doderlein's specimen, it seemed to me to be a good opportunity to avail myself of 

 Mr. Stewart's generous offer, and to describe the two species together. 



1. Metacrinus rotundus, sp. nov. (PI. L. ; PI. LII. figs. 1-7.) 



Dimensions. 



Length of stem to twenty-ninth node 44 centimetres. 



Diameter „ 5 millimetres. 



Longest cirrus, 45 joints \7 „ 



Diameter of disk IS ,, 



Length of arm after palmar axillary, 130 joints 125 ,, 



„ radial pinnule, 20 joints 20 „ 



„ distichal pinnule, 20 joints 20 ,, 



„ first pinnule after palmar axillary, 1 1- joints ... 9 „ 



Stem robust, with a rounded pentagonal outline. Usually eleven or twelve, but some- 

 times as many as eighteen intcrnodal joints. They have fairly well crenulated edges, 

 and their sides bear faint, more or less interrupted ridges, which sometimes become 

 slightly tubercular at the angles. These interradial tubercles are more marked on the 

 nodal joints, but vary considerably in size. The nodal joints increase in size from above 

 downwards as far as the lower edges of the wide cirrus-sockets, and then diminish again. 

 The sockets extend upwards above the articular surface on to the supranodal joints, 

 which are thus somewhat incised ; but each socket terminates below by a well defined 

 lip, which is distinctly above the lower edge of the nodal joint. The infranodals are not 

 incised to receive the cirrus-bases, so that the apposed syzygial surfaces are almost per- 

 fectly circular. The cirri consist of 40-45 very uniform squarish joints, the lowest of 

 which are but little wider than their successors. The cirri at the twelfth and next 

 following nodes are larger than those lower down. The intcrarticular pores disappear 

 between the eleventh and twelfth nodes. 



Basals pentagonal, rounded, and prominent. Padials usually five, with a syzygy in 

 the second, and occasionally another in the fourth or axillary. 



The rays divide three, or sometimes four times, giving 40-50 arms, which consist of 

 about 130 joints beyond the palmar axillary. They are tolerably smooth and but little 

 serrate in the mediodorsal line, except near the ends. 



Primary arms of 7-10, usually eight, distichal joints ; secondary arms of 10-18, usually 

 twelve or fourteen, palmar joints. There is occasionally another axillary after twenty or 



