■*! 



4 BALANIDJE. 



I have called the action of the cirri, captorial. When the 

 shell of a Balanus is broken open, the second and third 

 pairs of cirri are repeatedly clasped over the month with a 

 convulsive movement, in a manner indicating, I think, that 

 their chief function is to seize and carry to the mouth any 

 object entangled by the sweeping movement of the three 

 posterior pairs. The first pair is also well adapted to aid 

 in this seizing action ; but I suspect that the long anterior 

 ramus likewise acts as an organ of touch, warning the 

 animal of danger. The mouth being itself moveable as a 

 whole, — the outer maxillae being capable of a backward 

 and forward sweeping action, and being furnished with 

 orifices apparently olfactory, — the inner maxilla? having 

 more diversified movements, — the toothed mandibles over- 

 hanging the oesophagus, — and the oesophagus itself possess- 

 ing a powerful swallowing movement, are all admirably 

 adapted to secure any prey, when once entangled by the 

 cirri. 



Mouth, 



The mouth, in the sub-family Chthamalina?, cannot be 

 distinguished from that of the Lepadidae, which has been 

 pretty fully described in my former volume. In the 

 Balaninse, however, the labrum differs considerably in not 

 being swollen ; that is, in its outer and inner fold of mem- 

 brane being close together, and in having a central notch : 

 the palpi are also larger, and the lower teeth on the mandi- 

 bles, are laterally (PI. 26, fig. 5) double, as will be more 

 particularly stated under these two sub-families. I have 

 given a drawing (P\. 26, fig. 1) of the mouth, seen from 

 above, of Balanus perforatus, with the right-hand palpus {d') 

 and outer maxilla (a') cut off, in order that the labrum {e), 

 mandibles (c), and inner maxilla {b) might be better 

 shown ; the cut-off bases (a, a?) of the first cirrus on each 

 side are also shown. In fig. 2 we have the deep supra- 

 cesophageal cavity in Bal. improvisus torn open and laid 

 flat, with the inner surfaces of the labrum (<?) and outer 

 maxilla? (a) exhibited, the palpi, mandibles, and inner 

 maxillae having been removed. Figs. 3 and 4 will presently 

 be referred to ; they are parts of the mouth, with the mus- 



