SCHIZOPODA. 



465 



in the Hemitropha (Fig. 280, p. 438). The first maxillae are 

 usually small, two- or three-lobed plates, but in the Lophogas- 

 tridae a small dorsally directed process ending in long setae is 

 present, as in Nebalia, the Cumacea, and Chelifera. In this 

 family also a large setose exopodial plate of the second maxilla 

 is largely developed, homologous with the scaphognathite of 

 Decapods. 



The thoracic appendages are, as the name of the group implies, 

 divided ; having a leg -like endopodite and a many-jointed, setose, 

 swimming exopodite, and though in the Holotropha one or 



FIG. 289. Euphausia pellucida (after G. O Sars). a the adult male x about 8 ; b a luminous 

 organ from the tail ; c mandible. 



more of the anterior pairs have taken on the character of maxilli- 

 peds, they form, as a rule, a uniform series, in contrast with 

 differentiated condition found in the Decapods. There are 

 two basal segments, to the first of which (Hemitropha) or to 

 the arthrodial membrane connecting it with the trunk (Lopho- 

 gastridae) the gills are attached, and the second supports the 

 exopodite. In the Holotropha the epipodite of the 1st thoracic 

 limb is a simple branchial appendage (cf. Chelifera and Cumacea). 

 The Mysidae have no epipodial gills, apart from this appendage. 



In Gnaihophausia a small epipodial appendage on the distal side of 

 the gill springs from the basipodite (Sars) and this, as Caiman suggests, 

 may possibly be the homologue of the gill of the Hemitropha (cf. p. 4(58). 

 In the females of the Holotropha appendages of some of the thoracic legs, 

 modified as oostegites, form the brood pouch, as stated below. 



In some Mysidae lobed masticatory processes of the basal joint 

 of the first pair resemble those found in the limbs of Apus. In 

 z in H H 



