564 ORDER ABDOMINAL! A. 



the labrum, being produced into a special, lancet-formed 

 organ, articulated at its base and capable of movement, 

 and in the palpi projecting straight upwards, we have a 

 great difference from all other cirripedes ; and these 

 organs, we have every reason to believe, possess a high 

 classificatory importance. The oesophagus in Cryptophialus, 

 where it enters the stomach, is armed with teeth and 

 hairs, moved by muscles, forming a beautiful structure, of 

 which we have not a trace in any other cirripede. Lastly, 

 and perhaps most importantly of all, the metamorphosis is 

 different; for the early larval stages are passed under an 

 egg-like condition within the sack of the parent; and 

 the pupa differs from the pupae of all other cirripedes, in 

 not having natatory thoracic limbs, and is therefore only able 

 to crawl about by the aid of its great prehensile antenna?. 



Thus far the evidence is decisive in favour of Crypto- 

 phialus being placed in a separate Order ; but if we were 

 to trust to the characters derived from the external covering 

 or carapace, — and such characters are of high importance, 

 as w T e may safely infer from the natural arrangement of the 

 foregoing families which depends on the structure of the 

 carapace, — we should place Cryptophialus close to Alcippe 

 amonst the Lepadidae. These genera agree in their bur- 

 rowing habits, — in their attachment by a horny rostral disc, 

 — in the external membrane being covered with triturating 

 points, — in the spinose and notched orifice, with an external 

 lateral bar on each side, and in the inner tunic of the sack 

 being protected by hairs and spines. They agree to a con- 

 siderable extent in shape, and in the peculiar arrangement 

 of the muscles of the whole external covering of the animal : 

 they agree, also, in their manner of growth, and in the sack 

 extending down to their basal extremity. Some of these 

 resemblances may possibly be analogical, and due to simi- 

 larity of habits, and not to affinity; and we must attribute 

 to mere similarity in function, a certain amount of resem- 

 blance in their labrums, for this part is essentially different 

 in the two genera; and to the same cause, the resemblance 

 between the brush formed by the two pairs of thoracic cirri and 

 caudal appendages at the end of part of the thorax in Alcippe, 

 with the three pairs of abdominal cirri at the end of the 



