346 THE CANADIAN NATURALIST. [Vol. vi. 



nutrition may be readily observed in Anfedon, which will live for 

 months in a tank. The animal rests attached by its dorsal cirri, 

 with its arms expanded like the petals of a full-blown flower. A 

 current of sea water, bearing organic particles, is carried by the 

 cilia along the brachial grooves into the mouth, the water is ex- 

 hausted of its assimilable matter in the alimentary canal, and is 

 finally ejected at the anal orifice. The length and direction of 

 the anal tube prevent the exhausted water and the foecal matter 

 from returniog at once into the ciliated passages. 



In the probably extinct fimily Cyathocrinidae, and notably in 

 the genus Cyathocrinus, which the author took as the type of the 

 Palaeozoic group, the so-called Crinoidea Tessellata, the arrange- 

 ment, up to a certain point, is much the same. There is a widely- 

 expanded crown of branching arms, deeply grooved, which 

 doubtless performed the same functions as the grooved arms of 

 Pentacrinus ; but the grooves stop short at the edge of the disc, 

 and there is no central opening, the only visible apertures being 

 a tube, sometimes of extreme length, rising from the surface of 

 the disc in one of the inter -radial spaces, which is usually greatly 

 enlarged for its accommodation by the intercalation of additional 

 perisomatic plates, and a small tunnel-like opening through the 

 perisom of the edge of the disc opposite the base of each of the 

 arms, in continuation of the groove of the arm. The functions 

 of these openings, and the mode of nutrition of the crinoid having 

 this structure, have been the subject of much controversy. 



The author had lately had an opportunity of examining some 

 very remarkable specimens of Cyatliocrinus arthriticus, procured 

 by Mr. Charles Ketley from the Upper Silurians of Wenlock, and 

 a number of wonderfully perfect examples of species of the genera 

 Actinocrinus, Platycrinus, and others, for which he was indebted 

 to the liberality of Mr. Charles Wachsmuth, of Burlington, Ohio, 

 and Mr. Sydney Lyon, of Jefi'ersonville, Indiana ; and he had 

 also had the advantage of studying photographs of plates, showing 

 the internal structure of fossil crinoids, about to be published by 

 Messrs. Meek and "VYorthen, State Geologists for Illinois. A 

 careful examination of all these, taken in connection with the 

 description by Prof. Loven, of Hyponome Sarcii, a recent crinoid 

 lately procured from Torres Strait, had led him to the following 

 general conclusions. 



In accordance with the views of Dr. Schultze, Dr. Liitken, and 

 Messrs. Meek and Worthen, he regarded the proboscis of the 



