REPORT ON THE CRUSTACEA MACRURA. 



Tribe. 



Family. 



Subfamily. 



219 

 Brephalos. 



o 



to 



< Penaeidea, . 



P E N j£ I D JE, 



Genus. 



Pemeus. 



Philonieus. 



Artemesia. 



Halijiurus. 



Sicyonia. 



Hemipenxus. }- Nauplius? 



Aristeus, 



Hepomadus. 



? Peteinwa. 



Benthesicymus, 



Gennadas. 



H 



to 



< -l 

 « 



PQ 



Schizopoda, . -j 



Sergestid-e, . 



EuPHATJSID/E, 



LOPHOGASTRIDS, 



EuCOPIDiE, 



Mteidx, . 



SERGESTINiE, 



Luciferinj;, 



I'ctali'lituti. 



»S'f lY/l.vfl-H. 



Sciacarus. 



Art frx. 



Lucifer. 



Eucopia. 



Elapkoearis? 

 Nauplius. 



NaupHus ? 

 Metanauplius. 



Group NOEMALIA. 



The species of this Group differ considerably from one another in their appearance 

 and general structure, but throughout these many changes there is a gradual depreciation 

 of certain parts. Thus in the Penseidse the anterior three pairs of pereiopoda are chelate. 

 In the Sergestinae there are only two, and in the Luciferinse there is only one in this 

 condition. The first pair loses the chelate condition in the Sergestinae ; the first and 

 second in the Luciferinae. The third is largest in the Penseidaa, and is the last that retains 

 the chelate condition in the Luciferinse, where the chela has become microscopic. 



Those species that approach nearest in appearance to other groups have the posterior 

 two pairs of pereiopoda best developed. This is well seen in Sicyonia and Penwus, but 

 in Benthesicymus, Gennadas, and Sergestes they gradually diminish in size and power, 

 and in Acetes and Lucifer they disappear altogether. 



The branchiae are well developed in the Penaeidse. They diminish in number and 

 importance in the Sergestinae, and disappear in Lucifer. 



The form of the brephalos is supposed to be that of a Nauplius in the Penaeidae. It 

 is thought to be the same in the Sergestinae, but has not been traced nearer than an 

 Elaphocaris with a Nauplius eye, whde Mr. Brooks has demonstrated it to be of the 

 Nauplius form in the genus Lucifer. 



Thus widely separated as Lucifer may be from Penseus, they both possess the same 

 structural character, the one highly developed, the other in a depauperised condition. 



