402 



STOMATOPODA. 



represent the five maxillipeds of the adult 1 . The portion of the body 

 behind this is without appendages. It consists of three short anterior 

 segments, the three posterior thoracic segments of the adult, and a long 

 unsegmented tail. The three footless thoracic segments are covered by the 

 dorsal shield. Both pairs of antenna? ai-e nniramous and comparatively 

 short. The mandibles, like those of Phyllopods, are without palps, and the 

 two following pairs of maxillae are small. The five maxillipeds have the 

 characters of normal bii-amous Zoaea feet. From the front of the head 

 spring a pair of compound eyes with short stalks, which grow longer 

 in the succeeding stages; between them is a median eye. The dorsal 

 shield is attached just behind this eye, and is provided, as in the typical 

 Zosea, with a frontal spike while its hinder border is produced into two 

 lateral spikes and one median. In a larva of about three millimetres a pair 

 of biramous appendages arises behind the three footless thoracic segments. 

 It is the anterior pair of abdominal feet (fig. 226). The inner rarnus of 

 the second pair of maxillipeds soon grows greatly in length, indicating its 

 subsequent larger size and prehensile form (fig. 227 g}. When the larva 

 after one or two moults attains a length of six millimetres (fig. 227) the 

 abdomen has six segments (the sixth hardly differentiated), each with 

 a pair of appendages (the two hindermosb still rudimentary) which have 

 become gradually developed from before backwards. The three hindermost 

 thoracic segments are still without appendages. 



Some changes of importance 

 have occurred in the other parts. 

 Both antennae have acquired a 

 second flagellum, but the man- 

 dible is still without a palp. 

 The first and second pair of 

 maxillipeds have both under- 

 gone important modifications. 

 Their outer ramus (exopodite) 

 has been thrown off, and a gill- 

 plate (epipodite) has appeared 

 as an outgrowth from their 



basal joint. Each of them is composed of six joints. The three following 

 biramous appendages have retained their earlier characters but have become 

 much reduced in size. In the subsequent moults the most remarkable new 



FIG. 226. SECOND STAGE OF EBICHTHUS LARVA 

 OF SQDILLA WITH FIVE MAXILLIPEDS AND THE FIRST 



PAIB OF ABDOMINAL APPENDAGES. (From ClaUS. ) 



FIG. 227. ADVANCED EKICHTHUS LARVA OF SQUILLA WITH FIVE PAIRS OF ABDOMINAL 

 APPENDAGES. (From Glaus.) 



/. first maxilliped ; g. second maxilliped. 



1 These five maxillipeds correspond with the three maxillipeds and two anterior 

 ambulatory appendages of the Decapoda. 



