II UED E M A X X— SkssI LE ( ( iXI ' I. A Ml A. 



711 



assumption that tlieir interior was filled with muscular tissue, and con- 

 sequently connected with the circulatory system of the living animal. The 

 writer was unable to study this question on account of the negative results 

 which followed his attempts to isolate the appendages ; neither did he 

 succeed in tracing the confluent canals, indicated by the cross of pyrite at the 

 apex of the shell, which may have effected a connection with the interior of 

 the pyramid and thereby have become instrumental in producing a vacuum 

 by the withdrawal of a fluid, similar to that found in the pedicels of the 

 echinoids. The writer, however, is inclined to suppose that there existed no 

 connection whatever between the interiors of the pyramid and of the 

 appendage, but that attachment was effected by the elasticity of the latter 

 alone, especially by that of the central cup. The organ might then be 

 compared to the chitinous suckers with which the males of certain water- 

 beetles (e. </., JEhmectes) are provided, and which possess no muscular tissue 

 whatever but adhere to foreign bodies by external pressure and by sub- 

 sequently resuming the original shape through their own elasticity, thus 

 producing a vacuum much like the India rubber plates which are used to 

 fasten objects to the glass panes of show -windows. The shape of the central 

 cup as well as the fact that the appendage consists of a substance which 

 certainly was elastic, could be adduced in favor of this supposition, while 

 there seems to be no serious obstacle in the way of assuming that the animal, 

 which no doubt had a certain power of free moving, had the further 

 power of pressing the apex of the shell and with it the securely fastened cup 

 to the body it wished to adhere to. 



The diagrammatic section, figure 21, Plate III, is intended to illustrate the 

 working of the apparatus, the dotted part representing the latter in the 

 state of compression preparatory to attachment, and the striated part show s 

 the same in the state of attachment by suction. 



It should be remembered that however erroneous the attempt to explain 

 the special operation of this organ may be, this does not affect the fact that 

 the attachment was evidently only a temporary one and that the impressions 

 left by the appendages show both the connecting film and the central cup 

 bulging inward. These observations can, in the opinion of the writer, be 

 only accounted for by the assumption that the basal appendage was an organ 

 of attachment by suction. 



The publication of the concluding part of this article on Conularia 

 gracilis, Hall, has been much delayed because of a fortunate discovery 

 during the past summer (1896) of a locality on the bank of the East 



I 



