belonging to a new Order of the Class Cirripedia. 307 



which can be closed or opened at the will of the animal ; in front 

 they gradually blend with the mantle, behind they are deeply 

 notched, and each terminates in a projecting, slightly curved 

 point, d. The external surface of these valvular lips is furnished 

 with numerous, minute, irregularly disposed, rather stout, curved 

 spines, very transparent and of a crystalline appearance. The 

 circular, depressed, disc-like portion of the animal, corresponding 

 to the pedicle of the pedunculate Barnacles, is slightly arched 

 below, where it is pale, soft, fleshy, and as highly contractile as 

 the anterior portion or head : the upper surface is flat, and has 

 in the centre a broadly ovate, horny plate (figs. 3 & 5 e), most 

 distinct in old individuals, but never entirely covering the part, 

 the margins always extending beyond it. This plate is of a red- 

 dish horn-colour, and is generally furnished with a few indistinct 

 radiating ridges and tubercles corresponding to the radiating 

 lines and punctures seen on the surface of the matrix. 



The animal, as before stated, lies immediately below the sur- 

 face of the matrix, and is entirely free except at a point just be- 

 hind the slit, g, and in front of the horny plate where there is a 

 strong muscular attachment to the upper wall of the chamber. 

 The longitudinal opening of the animal corresponds to the slit 

 on the surface of the matrix : this opening is kept pretty accu- 

 rately plugged by the thickened valvular lips of the animal, ex- 

 cept when it is in watch for its prey, at which time a slight 

 opening in front permits the passage of the prehensile arms 

 (PI. VIII. figs. 3, 6 & 7/, d & e, and PI. IX. fig. 1). These 

 occupy the same position within the head or neck as they do in 

 the valvular part of the pedunculate Cirripedes, being placed 

 immediately in front of the mouth. They differ however consi- 

 derably from those of all other Cirripedes. The arms of this 

 animal are only six in number ; they are short and set in a circle 

 on the extremity of a soft, fleshy, cylindrical pedicle (fig. 6 c) y 

 which is undoubtedly a prolongation of the true body of the 

 animal ; the circle opens a little behind in the direction of the 

 mouth. The arms are each composed of three articulations, the 

 first or lowest being much the longest, the last the shortest ; 

 they are all furnished with a few hairs on the margins and extre- 

 mities : the four arms next the mouth have attached to their in- 

 ner margins at the junction of the first and second articulations 

 an oval cushion-like body (PI. VIII. fig. 9, and PI. IX. fig. 1 b b) 

 placed longitudinally, and wrinkled transversely, most probably 

 for the purpose of prehension. Immediately behind the arms pro- 

 jects a large conical body (PI. VIII. fig. 6/ and fig. 7 a) con- 

 taining the mouth (fig. 6 e & fig. 7 e 1 ), which is placed near the 

 base in front towards the circle of arms. The greater portion of 



21* 



