302 Miscellaneous. 



larife represent it, though there is uncertainty respecting the actual 

 forms to he identified with Calamites. The roots were given oflF 

 from the lower part of each internode, but above the node, and 

 were apparently epidermal. 



Tliere is also considerable doubt respecting the fructification of 

 Calamites. Some of the Volkmannise have evidently belonged to 

 this group ; but only one example retaining its minute organization 

 has yet been found in which the structure of the central axes corre- 

 sponded with that of the Calamites. The relationship to Calamites 

 of the fruits figured by Binney under the name of Calamodendron 

 commune, which are identical wth the Volkmannia Binneyi of Carru- 

 thers, is more than doubtful, because of the anomalous structure of 

 their central axes. 



After a careful comparison of the organization of Calamites 

 with that of the recent Equisetaceae, the author prefers constituting 

 the former an independent order, distinct from, though allied to, 

 the Equisetums, under the name of Calamitacece, and characterized 

 by cryptogamic fructification and verticillate foliage, associated with 

 an exogenous axis. The latter feature probably involved the exis- 

 tence of something resembling a cambium layer, furnishing the 

 material for the new tissues. 



It is further proposed to divide these plants into two generic 

 groups, viz. Calamites and Calamopitus — the former to comprehend 

 those unprovided with infranodal canals, and the latter those which 

 possess them. The existing specific distinctions appear to have 

 little or no scientific value. 



MISCELLANEOUS. 



On a new Sj^ecies of Three-toed Sloth from Costa Hiai. 

 By Dr. J. E. Geat, F.KS. &c. 



Arcfopithecus griseris. 



Fur very long, greyish white; under-fur very, abundant, brown; 

 forehead and cheeks white : crown and temples black; chin and 

 throat brown. Male with a yellow patch of soft hair betw^een the 

 shoulders, with a central black streak. Female with a puff of very 

 soft white hair on each side of the back. 



Hah. Costa Rica (Salvin). Brit. Mus. 



On a new Form of Sponrje. By Prof. Ehleks. 



Aulorhipis elegans, n. g. et sp. 



The stratified tissue of this sponge, which encloses many foreign 

 bodies, lines the inner surface of a worm-tube, from the superior 

 opening of which it projects in the form of a little stalk, which forks 

 into two branches bending downwards in the same plane, and gives 

 off from each branch several (eight to ten) twigs directed upwards. 



