LUCEllNAUl.E AND TllElR ALLIES. 87 



lies near the distal extremity of the latter, the first being indicated by a slight pro- 

 tuberance (0C-), dotted witli a few neniatocysts, and the last presenting itself under 

 the guise of a huge, broad, oval mass (oc'O, furrowed along one side, and simulating 

 a coffee-bean in pro])ortion and physiognomy. As an intermediate stage between 

 these two last, we offer for inspection a figure of the anchor {J'uj. 2-3) of an indi- 

 vidual whicli Avas two-thirds grown, or about three-fifths of an inch across the 

 umbella. This vie\f is designed principally to show the proportionate size of the 

 nematocystophore (oc"), and its relation to the longitudinal furrow of the colletocys- 

 tophore (oc'^), and the latter is, therefore, foreshortened from its proximal face. 

 The nematocystoi)hore (oc^) still projects above the level of tlie main mass which 

 surrounds it, the meagre remnant of a once vigorous organ. It will be seen, from 

 these tliree views, that the cliange which transports the nematocystophore in the 

 youngest stage to the extreme distal end of the colletocystophore in tin; fully 

 grown animal, consists in the development of a very large proportion of the coUc- 

 tocystic mass on the proximal side of the clear space (oc'^) from which the tentacular 

 knob arises, and consequently throwing the latter into the extreme oppoisitc direc- 

 tion. Accompanying this process there is also a gradual broadening of the mass 

 until it becomes so much wider than the peduncular portion that the latter appears 

 slender when contrasted with its former relative proportions in the penultimate and 

 antepenultimate stages. We return now to the general description of the organs 

 of the phase with which this section Avas opened. 



174. The Miiscidar Si/Htem. — The inconspicuous marginal muscle of the last 

 phase has become in this a sharply defined, ribbed band {fi^j. 58, ?»'), running 

 along the same line as in the full grown animal. We have endeavored to display 

 its internal face in our illustration by cutting open the circumoral parietes and 

 throwing it back so as to expose its interior surface. From this point of view, the 

 band may be seen thinning out, and finally disappearing as it reaches the base of 

 the tentacular group. Concerning the rest of the muscular system we have nothing 

 to say, except that the ridges of the opsomyoplax, in the lunbella, are so well ■ 

 developed that the circumoral face presents as great a diversity of physiognomy, as 

 far as these ridges affect it, as in the full grown animal, althougli not so strongly 

 marked and conspicuous. 



175. Be2>rodv,ctive Organs (f<jf. 67-73). — A clear understanding of the mode 

 of development of tlie reproductive organs oi Jjuceniarue is of paramount import- 

 ance, for more reasons than one. In the first place, they lie at the foundation of 

 the ty2>e idea of this order, and, therefore, their exact relations to tlie walls of the 

 umbelln, and to its (^xteritn* and interior faces should be made manifest from all 

 points of view. Their initiatory stages will, therefore, present them in their simplest 

 form and connections, before they have become so complicated and extended as to 

 obscure, more or less, the membranes from which they arise. This is, moreover, 

 quite essential, because they can at that period be compared most readily with the 

 reproductive organs in the other orders of Acaleplue. In the second place, we 

 shall not find it so difficult to comprehend the situation of the inverted wall of the 

 fully developed genital sac, witli all its convolutions, if we trace it, step by step, from 

 its simplest condition up to its most complicated form; and, again, the two cate- 



