136 Scientific Intelligence. 



tion, has the 4 anterior feet non-prehensile ; but in his figures, these feet are sub- 

 prehensile though minute, and they resemble in this, many AmphUoe, Orchestice, and 

 Allorchestes. The two anterior feet of the Talitri vary widely, from an obsolescent 

 hand to a large strong prehensile form. Here as elsewhere in nature, there is no 

 saltus in the gradations to aid us in generic groupings. 



The larger part of the new genera recently added, have been instituted by Kroyer 

 from species obtained in high northern latitudes. It is remarkable that the form in 

 this tribe should be so greatly varied in the colder seas, and confined to so few gen- 

 em in tropical latitudes. 



Fam. L ORCHESTID.E. 



1. Pedes secundi non subcheliformes. Antennae su- 



periores basi inferiorum breviores. Talitrus (Latreille). 



2. Pedes primi secundique subcheliformes. Antennae 

 superiores basi inferiorum breviores. Maxillipedes ad 

 apicem obtusi. 



3. Pedes primi secundique subcheliformes. Antennae 

 superiores breviores, basi inferiorum longiores. Maxil- 

 lipedes ad apicem unguiculati. Allorchestes (Dana.*) 



Orchestia (Leach), 



Fam. II. GAMMARIDjE. 



SlJB-FAM. I. LYSIANASSIN^. 



Antennae superiores ad basin crassse. Epimera grandia. Pedes sex 

 postici non prehensiles. 



I. Pedes subcheliformes nulli, secundis interdum exceptis. 



a. Pedes quinti sexti septimique directione similes. 



1. Antenna? superiores appendiculatae. Lysianassa (M. Edw.). 



2. Antennae superiores non appendicular. Phlias (Guerin). 



b. Pedes quinti tertii quartique directione similes. 



1. Antennae sup. appendiculatae. Palpus mandibula- 

 ris 1-articulatus. Stcgoc€phalus\ (Kroyer). 



II. Pedes primi subcheliformes, secundi non subcheliformes; reliqui 

 non prehensiles. 



1. Antenna* sup. appendiculatae. Opis\ (Kroyer). 



2. Antennae sup. non appendiculatae. Pedes secundi 



vergiformes; tertii quartique bre visa i mi. Uristes (Dana). 



III. Pedes primi secundique subcheliformes, reliqui non prehensiles. 



1. Antennae sup. appendiculatae. Anonyx§ (Kroyer). 



2. Antennae sup. non appendiculatae. Stenia (Dana). 



* The species of this genus have the aspect of many Amphitoe, and have proba- 

 bly been hitherto referred to that genus. They have the very short posterior stylets 



of the Orehesti®, and resemble them in habit and in the absence of a palpus to the 

 mandible; while they differ in having the superior antennae lonyst and in the stout 

 spine or claw terminating the maxillipeds. The writer has directed the mouth of 



■arly a dozen species of Allorchestes. 



f Kroyer's Naturhistorisk Tidsskrift, (Copenhagen,) iv, 150, 1842. " Caput ocnlis, 

 lit. videtur, destitutum." " Antennae breves (capitis altitudine non longiores)." u Pedes 

 quinti paris pedibus tertii quartique paris structura et directione similes." 



\ Tids., iv. L49. "Pedes primi pans chelis armati portentosae magnitudine. Re- 

 liqua cum genere Anonyce ferme conveniunt." 



§ Tids., ii, 256 and iv, 164. This genus is united with Tfffliflnftflflft by Milne Ed- 

 wards. Any species wholly without hands are properly Lysianassce ; those with 

 only two anterior hands, however minute or imperfect, belong to Opts. 



i 



