Remarks upon a Species of Cristellaria. 



121 



tagonal, with the lower margin strongly curved to receive the broadly 

 rounded lateral ends of the crescent-shaped ventral plate; upper dor- 

 sal' plate triangular; crescent-shaped ventral plate broad, with round- 

 ing ends; dorsal, dorso-lateral and upper dorsal, and the crescent 

 ventral plates are anchvlosed together; basal plate free; lateral 

 brachial plate narrow. The dorsal arm is broad at the base, and 

 contracts rapidlv for three joints, after which it tapers gradually, 

 throwing out two lateral branches from the sixth joint, and upon the 

 fourth joint from this are two more. Base of lateral arms formed of 

 three plates, the first of which is triangular, upon the two outer faces 

 of which there rest two plates; meeting in the center from each of 

 these there proceeds an arm; these arms are again branched upon the 

 upper side, apparently at every third joint. In the specimen from 

 which this description is taken, the upper arm can be traced ten 

 joints; upper branch of the lateral arms ten, and lower twelve joints. 

 The column was unfortunately lost, but its matrix shows it to have 

 been small, cylindrical and smooth. Lower part of the shale. 



AMERICAN PALAEOZOIC BRYOZOA. 

 By E. O. Ulrich. 



The researches of Dybowski and Liudstrom, and especially those of 

 Nicholson, amply demonstrate the fact that Chcetetes is eminently dis- 

 tinct from the Monticuliporidce, aud an3'thing I might say upon that 

 subject would simply be a reiteration of what those excellent observers 

 have already shown. The question of the S3 r stematic position of the 

 3Ionticuliporid(E, however, is not so firmly settled, and it is to 

 show, I hope, more clearly than it has been done heretofore, that this 

 family truly belongs to the Bryozoa, that the following remarks are 

 placed before my fellow laborers in this very difficult group of fossils. 

 I do not claim to know the reasons for, nor the uses of man}' of the 

 characters belonging to the Monticuliporidce, and my line of argu- 

 ment is, I ma} r say almost entirel}\ a comparative one, inasmuch as I 

 only attempt to show that the same features, more or less modified, 

 are present in a great number of undoubted Bryozoa belonging to the 

 sub-order Cyclostomata. 



Before proceeding with the subject it is necessary to explain the 



