Striiclufc of Il(il(i(jl(i'((. (hihid. 405 



formed of jellv. In transverse section they are like the thinnest 

 of pavement cells, 



The aboral canal, though small in diameter, is very clearly 

 detined, and as already described, oj>ens into the groove that 

 furrows one side of the organism, and ends in the conical pro- 

 jections on the aboral surface (Fig. 2). The wall of the canal is 

 formed of a definite gehitinous material which stains somewhat 

 more deeply than the ordinary jelly mass, and contains nuclei. 



Aboral Organ. In two specimens there is a curious but 

 definite bunch of projections associated with the aboral canal, 

 lying in the groove close to its external opening. Tlie bunch 

 of processes is transversed by sljort canals which open into the 

 aboral canal. (Figs. 7 and S. .\1. -J, Al. 3.) The body of the 

 whole mass is nuide of tlic same gelatinous nuiterial as the main 

 organism, with, however, a tendency to a til)rous formation. 

 Nuclei are scattered irregularly through it, but in addition to 

 these large numbers are arranged in definite relationship to the 

 external surface, and the walls of the canals (Fig. 7), indicating 

 a cellular formation, though no trace of cell outline can be dis- 

 tinguished. Most of the projections are club-shaped, and when 

 stained and cut in section show the structure represented in 

 Figure 8, Pr. There are a number of very definite dark bodies 

 often arranged in two roughly concentric series. The proces.ses 

 are apparently only solid masses of jelly in which these block- 

 like structures are embedded, and their arrangement and gene- 

 ral resemblance to what are evidently nuclei in other parts of 

 the processes and in the walls of the canals traversing the latter, 

 suggest the idea that they also are nuclear. If this be so they 

 are of large size in comparison with the cells with which thev 

 are associated. It is just possible that some of the canals open 

 on the surface of this enigmatic organ. In three parts there 

 are distinct indications of such openings, but I have not been 

 able to determine the point with certainty. 



The Oral Organ. — The only structure remaining to be de- 

 scribed is one that is present in four out of the fourteen speci- 

 mens ; no trace of it is to be found in any of the others. In 

 two of the four it is well marked. In Figure 3 a small process 

 can be seen projecting from the oral opening. It is attached 

 to the oral end of one of the cellular bands on the wall of the: 



