P E N M I D E A. gQ| 



Fam. II. Sergestim:.— Pedes toti debiles, 2di 3tiique consimiles, sive 

 vergiformes sive obsolete didactyli. Maxillipedes externi tenues. 



Fam. III. Eucopid;e. — Pedes toti debiles, 2di 3tiique non chelati, 

 lmi et maxillipedisque externi monodactyli et subprehensiles. 



In the single species of Eucopidae examined, the second pair of 

 maxillipeds is subprehensile and similar in its monodactyle character 

 to the third pair. These three pairs of monodactyle feet, anterior to 

 the four posterior thoracic pairs, approximate the species of Eucopidse 

 to the Squillidea. 



The following are the genera of living species in these families : 



Fam. I. PENiEID.E. 



G. 1. Sicyonia, Edw. — Pedes 6 antici lineares, 4 postici non annulati. Carapax 



breviter rostratus, semicalcareus, dorso carinato. Pedes abdominales laminS, una 



instructi. Maxillipedes 2di 3tiique non palpigeri. Antennae internae perbreves. 

 G. 2. Penjetjs, Latr.* — Pedes 6 antici lineares, 4 postici non annulati. Carapax 



elongato-rostratus, rostro ensiformi. Pedes abdominales laminis duabus instructi. 



Maxillipedes externi bene palpigeri. 

 G. 3. Stenopus, Latr. — Pedes 6 antici lineares, 4 postici longi, annulati. Eos- 



trum longitudine mediocre. Maxillipedes externi brevissime palpigeri. 

 G. 4. Spongicola, De Haan.-\ — Pedes 4 antici filiformes, 2 sequentes unus vel 



ambo crassissimi; 4 postici non annulati. Carapax bene rostratus, rostro suben- 



siformi. Maxillipedes externi non palpigeri. 



Fam. II. SERGESTID^]. 



G. 1. Sergestdes, Edw. — Carapax brevissime rostratus. Pedes thoracis non pal- 

 pigeri, 2di 3tiique obsolete didactyli, 5ti parvuli. 



G. 2. Acetes, Edw. — Carapax minute rostratus. Pedes thoracis non palpigeri, 

 2di 3tiique obsolete didactyli, 5ti obsoleti. 



G. 3. Euphema, Edw. — Carapax bene rostratus. Pedes thoracis elongato-palpi- 



* It is doubtful if Aristeus of Duvernoy (Ann. des Sci. Nat., xv. 1841, pi. 4) should 

 be separated from Penseus, with which it agrees in form, legs, antennae, &c. The form 

 of the branchiae is somewhat peculiar, but they are not essentially diflFerent in structure 

 from those of the Penaei. 



f Faun. Japon. Crust., p. 189, tab. 46, f. 9. 



151 



