PODOPHTHALMIA. 55 



position ; outer antennae sometimes posterior to eyes, but not exterior ; 

 abdomen small and applied closely to sternum; caudal extremity 

 without lateral appendages. 



II. ANOMOURA MEDIA. Hippidea and Porcellanidea : eyes not ante- 

 rior in position to inner antennae; outer antennae posterior and exte- 

 rior to eyes; caudal extremity with lateral appendages; abdomen 

 rather large and free, or laxly applied to the sternum. 



III. ANOMOURA SUBMEDIA. LitJtodea: eyes anterior in position to 

 inner antennae ; abdomen broad and not symmetrical, without caudal 

 appendages ; second, third, and fourth pairs of feet, similar. 



IV. ANOMOURA INFERIORA. Paguridea and Galatficeidea : eyes ante- 

 rior in position to inner antennae; abdomen large, hardly inflexed, 

 and having lateral appendages to caudal extremity. 



Reaching the Macroural level, we find no longer a few species only 

 to a type, as in the Anomoura; there is a vast development of forms 

 with even a smaller variety of types. A distinct system of structure 

 is arrived at, which is not of the nature of a transition or mixed style 

 of insect-architecture, but a perfect and simple style of itself, and 

 upon this system as a basis, the number of modifications is exceed- 

 ingly large. There is a surprising fertility in the expressions of the 

 one idea exhibited in the Macroural structure, and we cannot fail to 

 admire the infinity of resource displayed which is the more won- 

 derful as it is not developed where the diversity of types and grades 

 favoured diversity of forms, as in the Anomoura, but in a single grade, 

 and as the development of a single defined thought. 



Among the Macroura there are not those marks of imperfection 

 found in the Anomoura. The posterior thoracic legs are well deve- 

 loped; the abdomen is not a sluggish unwieldy mass, as in the Paguri, 

 but has a graceful outline and members to aid in its motions; and the 

 general figure of the body has not the half-finished aspect, the abor- 

 tive appearance, and clumsy limbs, which are so unlike either the 

 true Brachyura or Macroura. There is a balance in the forces, which 

 gives perfection to every organ, and all portions are like the well- 

 ordered parts of a harmonious structure. 



In rising from the Macroural grade to a higher, the great point of 

 progress lies in the more efficient or concentrated character to be 

 given to the organs of the senses; as these are the centres of force, 

 they are therefore highest in the power required for elevation. 



Among the lower Brachyura, the Grapsoidea, the posterior legs are 



