EEPOET ON THE AMPHIPODA. 603 



Orchestia selJcirki, n. sp. (Pis. I., II.). 



The Head is somewhat longer than the first segment of the pleon ; rostrum rudi- 

 mentary. Perseon moderately dilated ; beyond its fourth segment the body tapers 

 rather rapidly to the telson. Segments not greatly differing in length ; first of the 

 pleon the longest. The first three pleon-segments are postero-laterally squared, the 

 angles very slightly outdrawn, and the margins above them serrate upwards. 



Eyes roundish to oval, conspicuously black in the spirit specimens ; distance 

 between the two equal to the smaller diameter of one. 



Upper Antennae. — Three joints of peduncle small, successively decreasing much in 

 thickness. Flagellum shorter than peduncle. In the male specimen figured the 

 flagellum on one side had nine joints, that on the other only eight. In the female the 

 flagellum had only six joints. 



Lower Antennse. — Last two joints of peduncle long and stout, the last thinner than 

 the preceding. The tapering flagellum consists of about twenty-eight joints, all except 

 the last one or two distally widened. 



Upper Lip with rounded distal border minutely furred, the hairs on either side 

 inclinino' towards the centre of the margin. 



Mandibles. — The cutting edge of each mandible ends in a strong double tooth, 

 preceded in the left-hand mandible by four, in the right-hand by three or four smaller 

 teeth ; the secondary plate, on the left mandible, resembles the cutting edge, except that 

 it ends in a single tooth and is less powerful ; on the right mandible it has a bidentate 

 termination, the ridges of the doul^le tooth being minutely denticulate, and preceded by 

 three inconspicuous teeth. The spine-row consists of four sinuous plumose bristles, two 

 stout and two thinner ones. The prominent molar tubercle has the oval face set with 

 numerous rows of denticles. There is a long plumose bristle at one corner, and a sort 

 of hairy tuft at the opposite corner. I can find no trace of any rudimentary articulated 

 palp, such as is figured by Savigny for Orchestia montag^d and Gueriu for " Orchestia 

 gammarella." There is a prominent lobe rising just above the base of the molar tubercle, 

 obviously connected with the articulation and movement of the mandible, which has 

 perhaps in other species suggested the presence of a palp. 



Lower Lip. — The principal lobes very slightly dehiscent ; the mandibular processes ' 

 broadly rounded, not projecting far. 



Fi^'st Maxilla?. — The inner plate narrow, tipped with two plumose bristles, its inner 

 edge nearly straight, the other edge sinuous ; the broad outer plate is distally edged with 

 nine denticulate teeth in a double row. Just below the broadest part of the plate, 

 within the outer rim, springs a minute palp consisting of one slender joint, at the tip of 

 which a little pimple may be the rudiment of a second joint or of a spine. 



' See Note on S(;lii0dte, 1875 (p. 449). 



