VICTORIAN NATURALIST 73 



imder tlie microscope, as m8in]:)8i'3 will be able to judge for 

 themselves, if the f will lo'oE^'ftlip mounted specimens which I 

 exhibit, and which have been prepared for me by"5rrr°°Barnard, 

 the well-known member of the Microscopical Society, with his 

 usual kindness and skill. 



I have also made drawings showing these U^ tfT'JQ Jf^ ft variously- 

 magnified, which will serve the purpose of showing their chief 

 points of structure. 



In U. laterifora , the utricles are colourless, transparent, 

 s o mew na t pear p !i n ped bodies mounted on a slender stalk as 

 lonij; as, or a litlle longer than, their own greater diameter. 

 Their surface is marked with delicate wavy lines- and small 

 dots representing papillae At the thinner end is a kind of 

 snout, (called by Darwiii_ the antenna,) which is bent down over 

 a minute opening in the bladder. This entrance is protected by 

 a valve opening inwards only by one free edge, which rests 

 against a semiciKa.alai'', collar of several rows .of.-=sm.all cells 

 projecting into the bladflcr. Between the collar and the stalk 

 on the outer sxu?face of the bladder, are a number of curiously« 

 shaped pt^pill?-? or glands, formed a[>parently of three cells, the! 

 lowest being a truncated cone, the middle resembling a collarj 

 and the top one. a globe. These papillae seem to take the place 

 of the ]")rist1es ol-Berved by Darwin in the aquatic species. The 

 bjaddey presents one remarkable difference from those described 

 by Darwin : there is only one snout or antenna, not a pair. The 

 inner surf^ice of the bladder is studded with minute four-armed, 

 glandular processes, each on a short footstalk. The arms are 

 nearly equal and vary in position, from a cruciform shape to each 

 pair being nearly parallel, the arms are of about equal length, 

 (these differing from those described by "Darwin V and each 

 consists of a single cell. The vascular bundle of the footstalk 

 of the utricle may sometimes be traced nearly round the outer 

 edge of tne bladder, and one branch runs along the ventral 

 surface, to the point of the snout. This seems to indicate that 

 the b ladder is a rnodified leaf , that is, a leaf folded down the 

 midrib, somewhat in the manner of a carpel. 



The valve itself is said to be a rather complicated structure, 

 but I have not been able to dissect it out, and examine it. 



In U. dichotoma_ the bladders, are much larger, being about 

 ^ inch in diameter, and minute points of structure could 

 probably be more easily seen, and dissection would not be so 

 difficult as in the smaller species. As I had, however, only dried 

 bladders of this plant, I could not see much structure; prolonged 

 soaking and very careful washing might make even these fit for 

 observation. I could see that they resembledi much more 

 closely the U. mdc/arts than did U. lateriflora, the antenna being 

 slender and branched, and the opening to the valve being 

 surrounded by bristles. 



