Order Lucernaria;. 537 



to the end of each arm : marginal muscle broad and thin, 

 forming a sort of velum which projects beyond the margin 

 of tiie aboral side ; at the end of the arms it merges into 

 the ligulate muscles of the oral side of the disc : gelatini- 

 form layer of the aboral side, and the pedicel, conspicuous. 



Halimocyathus platypus. H. James-Clark. 



The disc or bell deeply infnndibuliform ; the arms nearly 

 twice as long as broad, and one third as long as the height 

 of the disc from the pedicel to the margin ; the marginal 

 sinuses no broader than the arms : the pedicel short, half 

 as high as the disc ; at the narrowest part, where it joins 

 the body, its diameter is nearly one half its length, and from 

 there it gradually broadens into a very large base, which 

 has a width equal to the length of the pedicel ; round, or 

 very slightly furrowed at four points opposite the muscles ; 

 in the middle of the base a small round opening lead- 

 ing to a cylindrical cavity, lined by the outer wall, which 

 projects into the gelatiniform axis considerably beyond the 

 horizon at which the pedicel • cameras terminate ; the four 

 camersB very large, closely approximated to each other and 

 to the axis, so that they have very narrow strips of gelatin- 

 iform substance between each other, or between them and 

 the axis; transversely quadrant ; altogether they occupy the 

 axial two thirds of the pedicel, and as the latter broadens 

 toward its base the camera broaden also, so as to retain 

 their proportionate size throughout; they open widely into 

 the cavity of the bell, neither at the base nor at any point 

 have they any intercommunication : tentacles thick, about 

 as long as the greatest breadth of the arms, seventeen to 

 twenty in each tuft, the radial diameter of the tuft much 

 greater than the transverse ; in a bunch containing seven- 

 teen there are seven tentacles in the middle radial row, 

 four in each row on either side of the latter, and one in 

 each outermost row, the last close to the distal side of the 



JOURNAL B. S. N. 11. 68 



