CRYPT0PH1ALUS MINUTUS. 569 



fig. 3), expands into an oblong, slightly rigid plate, studded 

 with from three or four to ten or twelve points, which have 

 their ends expanded and truncated, or even slightly bifid. 

 The extremity of this plate projects freely from the general 

 surface of the body. We shall afterwards refer to the use 

 of this extremely peculiar bar and plate. 



The two rims forming the orifice cannot be quite closed ; 

 but ingress by any foreign object into the sack is beautifully 

 prevented by an internal membranous lip on each side (</, 

 fig. 3, 4), and by a third inwardly folded lip {d') at the pos- 

 terior and broad end of the orifice. These three lips can be 

 brought together, and form a valve. The lateral lips are very 

 narrow at the mouth or rostral end of the orifice, where the 

 hairy lancet-shaped crest of the labrum closes the orifice, and 

 largely expand towards the posterior end : they are pro- 

 duced from the inner tunic of the sack : they appear formed 

 of the finest hairs, placed parallel and approximate, but when 

 examined under the highest powers, these hairs (for they 

 still appear such) are found to be united by delicate mem- 

 brane, which has its extreme edge fimbriated. The third, 

 or posterior and inwardly folded lip, differs in being com- 

 posed of much coarser, flattened hairs, which are united 

 towards their bases, and are free at their extremities, where 

 they are serrated or coarsely plumose on both sides. 



The sack extends down to the lower end of the animal. 

 It is lined by delicate membrane. At the orifice on each 

 side, a little posteriorly to the lateral external bars, this 

 inner membrane is strengthened by a pair of thin yel- 

 lowish bars (c, fig. 3), which run parallel to the straight 

 portions of the external bars. These inner bars at their 

 lower ends become pointed and die out: at their upper 

 ends, and close to the rim, they are broader, but more 

 flexible, and so transparent as hardly to be distinguished 

 from the rest of the membrane. At the rostral end of the 

 orifice, in a medial line, this same inner tunic of the sack is 

 thickened for a short space downwards, so as to form a fifth 

 bar {c") ; which separating from the inner tunic, runs in- 

 wards between the outer and inner membranes of the cara- 

 pace (i. e. between b and c, fig. 3, 5), behind the mouth, as far 

 down as opposite to the lower end of the oesophagus, and 



