CRYPTOPHIALUS MINUTUS. 583 



oval, to oval with three horns, and lastly to oval with the 

 two anterior horns larger, and the posterior horn reduced 

 to a mere point, seems to me very curious ; and offers, as 

 far as I know, a unique case. It is interesting to reflect 

 how perfect a series, in the development of an animal, we 

 have, in different members of the Articulata, — from an or- 

 dinary egg, in which all the changes go on unperceived, and 

 whence a perfect animal is matured, — to an egg-like larva 

 which undergoes the changes just described, and which 

 turns into a pupa that does not eat or increase in size, — to 

 a larva which eats and increases in size, but undergoes only 

 one great change, as in most insects, — to a larva under- 

 going several great changes, as in the case of ordinary cirri- 

 pedes, before its final metamorphosis into the mature animal. 

 The first larval condition of other cirripedes, in which there 

 is a single eye, three pairs of thoracic limbs, and a much 

 elongated pointed body, covered by a prolongation of the 

 carapace, is here not fully developed or matured ; but this 

 stage is, I think, clearly and very curiously indicated by the 

 posterior horn of the egg-like larva, which we may suppose 

 represents the posterior pointed end of the body, for it dis- 

 appears in the succeeding stage, just as it does in the second 

 larval condition of other cirripedes. In the first stage of ordi- 

 nary cirripedial larvae, the anterior horns are always present, 

 serving, as in the case of these egg-like bodies, to inclose and 

 protect the antennae during their formation. The second 

 egg-like stage answers to the second larval condition of 

 ordinary cirripedes, as described (and figured, PL 30, fig. 1) 

 in the introduction to the Balanidse. The third or pupal 

 state is fully developed in all cases. 



Finally, the pupa of Cryptophialus is peculiar in its 

 punctured, hairy surface, and in its shape, which, in being 

 so much more depressed than usual, retains an earlier larval 

 condition ; but its chief and highly remarkable character 

 consists in the entire absence of natatory legs ; and, in con- 

 sequence, instead of there being a large sack within the cara- 

 pace, with an elongated orifice on the ventral surface, there is 

 only a quite minute orifice at the extreme posterior end of the 

 animal, through which the bristles, borne apparently on all 

 three segments of the minute abdomen, are protruded. 



