Prof. J. Miiller on tJie Structure of the Echinodenns. 251 



sent year, he inquired further for the remains of the animal from 

 Gothland; and M. Loven was so good as to send to me for 

 description the beautiful fragments which he possessed of it. In 

 one of these specimens, the greater portion of the calyx with a 

 part of the hands is preserved ; in another, a part of the calyx 

 with the petaloid hands. A third specimen consists of the hands 

 alone. Prof. A. Retzius also sent me besides a beautifully pre- 

 served specimen of the hands. Who can contemplate without 

 joyful surprise these remains, in which the peculiar structure of 

 one of the most remarkable forms of the Crinoids is clearly 

 evident ? 



The base of the calyx, whose plates are perfectly smooth, is 

 not quite perfect, but appears to consist of five hasalia, on which 

 follow a circle of five parabasalia ; with these alternate five arm- 

 bases, radialia, which are in contact, there is, however, a small 

 intermediate piece between two of the five. This arrangement 

 would thus agree with Cyathocrinus. The parabasalia are hexa- 

 gonal; their breadth to their depth as 3:2. The basalia are 

 exceedingly depressed, three times as broad as they are deep. 

 On each of the basalia three joints are seated, — one, of a tri- 

 angular form, upon the excavated centre of the anterior edge ; 

 two at its sides ; the inner edges of the latter lie over the middle 

 piece, and so come into contact. These two lateral pieces are the 

 bases for all the series of joints of both halves of the hands. To 

 each are first attached two joints, an internal, and a far broader 

 external. The broader is the first of the longitudinal series of 

 broad joints which runs along the outer edge of the commence- 

 ment of the hand. At first very broad, they become successively 

 narrower; their outer edges constitute the outer edge of the 

 hand, while the inner edge is, as it were, cut into steps of two 

 joints, sufficiently deep to allow of a new series of joints being 

 articulated upon the notches thus formed. 



The step-like notches therefore pass over one, and further on 

 even many joints. The series of joints soon divides dichoto- 

 mously again, and the dichotomy is continually repeated. Even 

 at a small distance from the bases of the arms, we find more than 

 thirty longitudinal series in the breadth of a hand; at the 

 distance of an inch from the base of the hand there are as many 

 as eighty series, and so they go on multiplying. The joints lie 

 not merely in regular dichotomous longitudinal series, but in as 

 exactly regular arched transverse series, and are articulated 

 together laterally by opposed processes, so that all the joints of 

 the hand taken together form a petal with innumerable minute 

 gaps. These five hands have an extraordinary breadth at their 

 periphery ; in their expanded condition they would doubtless no 



