76 ACALEPH.E. 



as an intestine through which the residue of digestion is discharged. 

 From around the oral extremity of the stomach, and from the glo- 

 bular cavity in which the two principal canals terminate, arise ves- 

 sels, (, t, ,) which diverge so as to form a cone at the base of which 

 they all empty themselves into two circular canals, one surrounding 

 the mouth, and the other encircling the anal aperture ; which pre- 

 cisely correspond with the vascular rings already described in the 

 Beroe : and, from these, four long vessels, or branchial arteries as 

 they might be termed, (/?, p ; </, </,) are prolonged beneath the four 

 ciliated margins all around the body. But, besides these four nutri- 

 tive vessels, two others (#, x) arise from the anal ring which run 

 inwards towards the centre of the animal, and afterwards, assuming 

 a longitudinal direction, seem to distribute nourishment to the me- 

 dian portions of the body. The caeca or blind tubes, (w, w,) ap- 

 pended to the intestine, may possibly furnish some secretion use- 

 ful in digestion, although we are perhaps scarcely warranted in 

 saying decidedly that they are the rudiments of biliary organs.* 



Our information concerning the nutritive apparatus of the other 

 orders of acalephse is very limited. In Physalus (Jig. 24) and 

 Porpita (fig. 25), the suckers appended to the body would seem 

 to be the organs by which food is taken into the system ; but, of 

 the internal arrangement of the parts subservient to its digestion 

 and distribution, little has been determined satisfactorily. 



(103.) Extraordinary as must appear the powers which these 

 animals possess of seizing and dissolving other creatures, apparently 

 so disproportioned to their strength, and the delicate tissues which 

 compose their bodies, there are other circumstances of their history 

 equally remarkable, which in the present state of our knowledge 

 are still more inexplicable. If a living medusa be placed in a 

 large vessel of fresh sea-water, it will be found to secrete an abun- 

 dant quantity of glairy matter, which, exuding from the surface 

 of its body, becomes diffused through the element around it so 

 copiously, that it is difficult to conceive whence materials can be 

 derived from which it can be elaborated. Of the origin of this 

 fluid we are ignorant, although certain glandular-looking granules 

 contained in the folds of the pedicle have been looked upon as 

 connected with its production. 



(104.) We are equally at a loss to account for the pro- 

 duction of the irritating secretion in which the power of stinging 



* Delle Chiaje, Memorie per servire alia storia degli Animali senza vertebre del 

 regno di Napoli. 4to. 18231825. 



