502 CRUSTACEA MALACOSTRACA. 



Sub-fam. 6. Orchestiina. Head large, cubical. First antennae 

 simple and mandibles without palps. The brancliiae of the 3-5th 

 legs short and spirally twisted. The three last pairs of abdominal 

 legs short and powerful, the 6th with a single terminal lamella. 

 Terminal abdominal segment short and thick. Talitrus Latr. ; 

 Orchestia Leach ; Hyale Rathke. They frequent sea-coasts and 

 inland waters ; some species of Orchestia are terrestrial. 



Genera of doubtful position Uristes Dana ; Guerinia Hope ; and 

 Synopia Dana 



Division 2. HYPERINA. 



Head large and usually rounded. The greater part of its surface is 

 usually occupied by the very large eyes, which are more or less com- 

 pletely divided into frontal and lateral portions. Second antennae small or 

 rudimentary in the females. Maxillipeds much reduced and fused to form 

 a plate limiting the mouth cavity behind (Fig. 306). Thoracic legs differ- 

 ing from one another much in shape, with small basal segments. Pelagic. 



Tribe 1. HYPERINA ANOMALA. 



Both pairs of antennae lie in excavations on the under side of the head. 

 In the male the first pair has a swollen shaft, clothed with hairs, and bears 

 a rudimentary flagellum, the second is very thin and long and folded on 

 itself in a zigzag. In the female the second is short and straight. Sixth 

 and seventh thoracic feet with the second segment broad and lamellar. 

 The eighth is small or rudimentary. 



Fam. 1. Typhidae. Head swollen ; upper lip convex ; thorax broad, 

 somewhat depressed ; abdomen much narrower, short and capable of 

 being folded in against the thorax ; the lamellar plates of the 6th and 

 7th pairs of thoracic legs very large and covering the whole under 

 surface of the thorax. Eutyphis Claus (Platyscelus Sp. Bate) ; Hemity- 

 phis, Paratyphis, Tetrathyrus, and Amphithyrus Claus. 



Fam. 2. Scelidae. Head and thorax as in Typhidae but the mouth 

 parts projecting as a beak, the mandibles being narrow and elongated. The 

 abdomen longer. Tanyscelus, Parascelus, Schizoscelus and Euscelus Claus. 



Fam. 3. Pronoidae. Head rounded, arched ; both antennae present 

 in the female ; maxillae strong ; body elongated and slightly compressed ; 

 abdomen large ; plates of 6th and 7th thoracic legs of moderate size ; 

 eighth 1 rudimentary. Pronoe Guer. ; Eupronoe and Parapronoe Claus ; 

 Phorcus M. Edw. 



Fam. 4. Lycaeidae. Resembling Hyperia in shape of body. Second 

 antennae generally absent in the female ; maxillae feebly developed ; a 

 pair of " otosacs " above the brain ; plates of sixth and seventh thoracic 

 feet not much enlarged ; eighth pair with full number of segments. 

 Thamyris Sp. Bate ; Lycaea Dana ; L. pulex commensal in Salps. Para 

 lycaea, Pseudolycaea, Lycaeopsis and Simorhynchus Claus. 



Fam. 5. Oxycephalidae. Body elongated, laterally compressed, head 

 produced into a beak-like prominence ; 2nd antenna absent in the 

 female ; two " otosacs " above the brain ; 2nd and 3rd thoracic legs with 

 chaelae in which the two terminal segments are opposed to a process on 

 the ante-penultimate ; the 6th and 7th have slender plates, and the 

 eighth is complete ; abdomen large. Oxycephalus M. Edw., and Rhab- 

 dosoma White. R. annatum from the Atlantic and Pacific, one of the 

 longest Amphipods known, attains a length of 120 mm. 



