GIO 



MR. E. J. MIEES 01^ THE 



AVithin the Maiinea, a regular gradation of characters may be 

 traced from the forms (Lqytopodia and Stenorlrijnchus) witli non- 

 retractile and laterally projecting eyes and narrow basal* antennal 

 joint and elongated epistoma, at one end of the series, to those 

 (exemplified in Fericcra and Mitlirax) with deep circular and 

 well-defined orbits, transverse epistoma, and greatly developed 

 basal antennal joint, at the other ; and I accordingly distiugnish 

 among the Maiinea three principal groups, founded upon the 

 orbital and antennal characters, as will be seen in the following 

 tabular arrangement. 



Legion I. Maiinea. {Maiinea, Dana; Inachoidiens, A. M. -Edwards.) 

 Basal antennal joint well developed, inserted beneath the eyes, and 

 occupying a great part of the infraocular space. 



Family I. Inachid^e. E3es non-retractile, or retractile against the 

 sides of the carapace. No defined orbits exist ; but there is often a well- 

 developed pra30cular or postocular spine. Basal joint of antennae usually 

 very slender, sometimes moderately enlarged. 



Family II. Maiid.e. Eyes retractile within the projecting orbits, which 

 are more or less incomplete below the eyes, or marked with o])en fissures 

 in their u])per or lower margins. Basal antennal joint always more 

 or less enlarged. 



Family III. Pericerid.e. Eyes usually retractile within the orbits, 

 which are small, deep, and circular, never incomplete. Basal antennal 

 joint well-developed, and usually very considerably enlarged. 



As a rule, there can be no difficulty in assigning to any genua 



its place in one or other of the three families characterized above ; 



yet, as the Maiida) constitute a group intermediate between the 



Inachidae and Periceridss, there are certain genera which lie on 



the border line separating the Inachida) and Maiida?, w^hicb 



might be referred with almost equal justice to either family unless 



some artificial limit were imposed. In Loocorliynclius, for examj)]e, 



the prasocular and postocnlar spines and basal antennal joint are 



largely developed, and this genus approximates closely in its 



orbital and antennal characters to Fisa and its allies among the 



Maiinse; and, to take another instance, TycJie has its upper orbital 



margin as much developed as Acanthcplirys among the Maiidse, 



yet cannot be separated from its natural allies Stenocionops and 



Stilhognathus, which belong to the Inachidas. Again, among the 



Maiinea with deflexed front, it will be shown that a regular transi- 



''^ I use this term, in the sense commonly employed by authors, for tlie large 

 joint which is apparently tlie first of the basal portion of the antennae, but ia 

 in reality the Becond joint (" basicerite"). 



