166 



peds are described as having an epipodite, and the epipodites of the thoracic 

 legs are described as long and broad. In this Memoir, therefore, the name 

 Pentacheles is applied to the species (having the eyes imbedded in orbital 

 notches) in which the external maxillipeds have a recognizable epipodite, and 

 the first 4 pairs of legs have normal epipodites ascending into the branchial 

 chamber. 



Polycheles, Heller. 



Polycheles, Heller, Sitzungsb. Aknd. Wien, XLV. 1862, i. p. 389, and Crnst. eiidl. Europ., p. 209 : Spence Bate, 

 Challenger Croat. Macrnra, p. 126: Faxon, Mem. Mns. Conip. Zool. XVIII. 1895, p. 117. 

 Stereomastis, Spence Bate, Challenger Crust. Slacrni'a, p. 154. 



Carapace nearly as long as the abdomen, elongate-snbquadrilateral or 

 truncate-oval, usually depressed : its lateral borders are sharply defined as in 

 Brachyura, marking off (1) a dorsal surface, which is longitudinally carinated 

 in the middle line, and (2) a side-wall, which is traversed fore and aft by two 

 oblique ridges, one running to the base of the antenna? and corresponding with 

 the epimeral suture of the crab's carapace, the other running to the base of the 

 1st pair of thoracic legs. The cervical groove is well defined. The rostrum is 

 represented by a small spine or pair of small spines, its place being supplied by 

 an acute rigid prolongation of the inner border of the basal joint of the 

 antennules. In the frontal border, on either side, is a deep sinus, which is filled 

 by the immovable eye-stalk. The posterior border of the carapace in concave, 

 and the posterior angles of the carapace are nipped between two pegs at the 

 outer angles of the 1st abdominal somite, each peg fitting into a distinct socket. 



The abdomen is depressed and tapering, the telson, which is about as long 

 as the caudal swimmerets, being acute. The abdominal somites articulate wifli 

 one another by little hinge-joints situated near the tergo-pleural junction : the 

 terga are carinated in the middle line : the pleura of the 2nd somite are large 

 and auriculate. The exopodite of the tail-fan is not transversely fissured. 



The eyestalks are immovably impacted in the orbital notches : their greater 

 part is well calcified, but the part that fits the bottom of the notch is thin and 

 translucent and appears to represent the remains of the eye. From the frontal 

 end of the eye-stalk a slender blunt process runs outwards, at right angles, 

 beneath the antero-lateral lobe of the carapace : its somewhat translucent tip 

 may perhaps be the remains of the eye. 



The basal joint of the antennular peduncle has its inner angle produced to 

 form a sharp stiff lamina resembling (but usually larger than) the antennal 

 scale : of the two antennular flagella the inner one resembles, in form and 

 length, the antennal flagella, being longer than the carapace, while the outer one 

 is short and not stouter than the inner, even in the male. 



The antennal scale is an acute narrow lamina, not overlapping the antennal 



