54 AMi'UU'ODA NoltJI.M.IA. 



Subfamily 1. STEGOCEPHALIDES. 



Superior and inferior antenna? subequal. Coxae of the second pair 

 of gnathopoda and of the fii'st and second pairs of perciopoda 

 monstrously developed ; second paii' broader than the preceding. 

 Perciopoda subequal. Last three pairs of pleopoda styliform. 

 Telson single. 



Dana established his subfamily STEGOCEPHALixiE to receive Kriiyer's 

 genus Stegocephalus ; but there are several other genera that evi- 

 dciitly fall within this family, the points of their approximation being 

 of greater importance than those in which they differ. The pi'incii)al 

 feature, and one Avhich is readily appreciable, is the large size of the 

 coxa; of the two anterior pairs of perciopoda, which are capable of 

 enclosing all the appendages of the animal when rolled together. The 

 genera on the one side approach in character to the ORcnEsxiDiE, and 

 on the other to the Lysianassides. They may be arranged thus : — 



a. Superior antennae without an appendage ; mandibles without 



an appendage ; posterior pleopoda unibranched. 



b. Superior antenna? without an appendage ; mandibles with an 



appendage ; posterior pleopoda double -branched. 



c. Superior antennce with a rudimentary appendage ; mandibles 



■ndthout an appendage ; posterior pleopoda double-branched. 



a. Superior antennce without an appendage; mandibles without an 

 appendage ; posterior pleopoda unibranched. 



1. MONTAGUA. 



Leucothoe, Kroi/er (not Leach), Nat. Tick. iv. p. 141, (2) i. p. 539, 



1845. 

 Montagua, Sjjence Bate, Brit. Assoc. Report, 1855 ; Synopsis Brit. 



Amphiphoda, Ann. Nat. Hist. Feb. 1857. 



The superior antennae are as long as the inferior, and not fm-nished 

 with a secondaiy appendage. The mandibles are not fiu-nished 

 with an appendage. The maxillipeds are pediform, unguiculate, 

 and without, or with only rudimentary, squamiform plates. The 

 first pair of gnathopoda are small, subchelate, the coxae not 

 developed into a squamiform plate. The second pair of gna- 

 thopoda are larger than the first, and have the coxae very large, 

 squamiform, deeper than the body, and produced anteriorly, so as 

 to cover the organs of the mouth ; the propodos is developed upon 

 the same type as in the first pair. The perciopoda are subequal ; 

 the coxae of the two anterior pairs are very largely developed, 

 deeper than the body, and produced posteriorly, so as to cover that 

 of the following pair of perciopoda. The posterior pair of pleopoda 



