LUC ERNAR I iE AND THEIR ALLIES. 61 



function in question; and this is absolutely necessary to a proper understanding of the 

 limits of this system. That an Acaloph is possessed of a stomach or chyraiferous 

 cavity distinct from a general chyliferous chamber can only be asserted, even in 

 part, by admitting, as we certainly do not, the Ctenophorae into this class. That 

 the Ctenophorae have these two cavities is enough to rule tliem out of the circle 

 within which the Strobiloida, Lucernariae, and Hydroida are included. The 

 peculiarity of Ctenophorae approximates them, in this respect, i. e., functionally, to 

 the Polypi ; and some naturalists have even gone so far as to assert that they 

 belong there. We must confess that we do not see the faintest glimmer of a reason 

 for so doing. Those who are accustomed to making forced homologues, by supposing 

 this a little changed, and that a little something else, and tiie other not quite so 

 much so, and everything else a tithe otherwise than what it really is, can easily 

 twist the ideal Ctenopliore completely out of its type, even, withou*" knowing it, 

 and with a logical (illogical) jump land in the midst of a totally different category 

 of relations, and yet suppose that they have been standing still all the while. 



123. The Diijestire Carify Moncmierous. — The Lucernariae also have been classed 

 among the Polypi by all early observers, and even at this late day a place is claimed 

 for them there by some naturalists. The character of their digestive system alone 

 is enough to debar them from such an alliance. They challenge the closest homo- 

 logical comparison with the Acalephae, as we have limited the class above, and no 

 one who is at all familiar with their structure can fail to see their intimate relation- 

 ship with them. The food does not digest in the proboscis (Ji>j. 37, p), but is 

 transferred to the post-buccal or central cavity (4''^), and even to the lateral camerie 

 (\i/') of the umbella. We have often noticed, in the latter place in particular, quite 

 large shrimps undergoing the process of breaking down. There is, tlicrefore, no 

 subdivision of tlie digestive system into two parts, as in Polypi and Ctenophorae. 

 The food enters the mouth and glides through the proboscis (Ji<j. 37, p) as if the 

 latter were a mere conduit. It can scarcely be called anything else; assuredly it 

 does not present the appc^arance of a digestive organ, for of all parts of the digestive 

 system it is the least endowed with anything in the form of interstitial pigment or 

 brown glandular-looking matter ; and so far from being narrowed at its posterior 

 end, it opens widely there, and passes insensibly into the general central cavity (4"). 

 We might even say that the digestive surface of the system is more diffuse than in 

 the other two orders of Acalephae ; for in them the heavy, large masses of food 

 cannot gain access to the lateral passages of the umbella, the so-called cliymifcrous 

 tubes. There is, then, in the latter a closer approximation to tliat subdivision wliich 

 obtains in Polypi than exists in the digestive system of Lncernariap. Neither is 

 there any dividing line, structurally speaking, that separates the four camera? (r') 

 of the peduncle from the general cavity. Tliere is a slight constriction of the 

 breadth of space at their entrance (t^) and for a short distance posterior to that, 

 but nothing that approaches to a valvular apparatus, nor anything of the sort. In 

 Calvadosia, Lucernaria, and Mmuiuia the caudal chamber is singl(\ and passes 

 with widely spreading walls insensibly into the general unibellar cavity. Tlierc is 

 also very little or no restriction to the entrance of the uinbellar fluid into the 

 tentacles and anchors of Haliclystus. If we look for accessory organs to the main 

 digestive cavity, we meet with no glands, nor anytliing that approaclms such a 



