CALLIOPIIDAE i S7 



Antenna i stout, ist joint with apices somewhat produced, 3rd with lower apex pro- 

 duced, flagellum with very short, broad joints, with rows of short spine-setae on lower 

 distal margin, no accessory flagellum. Antenna 2 stout, broken. Upper lip apically 

 rounded. Lower lip, outer lobes broad, transverse, inner lobes inconspicuous, ap- 

 parently fused. Mandible, cutting edge dentate, spine row of five spines, molar 

 moderate, palp large, 3rd joint a little shorter than 2nd, with a regular series of marginal 

 setae. Maxilla 1, inner lobe with two setae, outer lobe with four large spines and one or 

 two smaller ones, palp 2-jointed, apex with several spinules. Maxilla 2, outer lobe 

 longer than inner, both equally broad, inner with distal setae, but proximal half of inner 

 margin with fine setules only. Maxilliped, inner plate with three apical spinules, outer 

 plate with setules on inner margin, and two apical spines. 



Gnathopod 1, 5th and 6th joints subequal in length, 6th slightly broader than 5th, 

 oblong, palm transverse, with rounded denticles and defined by two spines, finger 

 matching palm, inner margin serrate. Gnathopod 2, 5th joint very small, 6th very 

 large, oblong, lower apex produced to form a thumb, with its upper margin crenulate, 

 finger matching thumb, its inner margin only very faintly crenulate. 



Peraeopods stout, subsimilar; in peraeopods 1 and 2 anterior margin of 4th and 

 posterior margins of 5th and 6th joints notched at insertions of the spinules ; in peraeo- 

 pods 3-5, 2nd joint ovate, postero-inferior angle rounded, posterior margin entire or 

 only very faintly notched, posterior margin of 4th joint and anterior margins of 5th and 

 6th notched at insertions of the spinules. 



Uropods lost. Branchial lamellae simple. 



Remarks. It is a great pity that the single specimen of this remarkable form should be 

 mutilated. The ends of the antennae, the 5th and 6th pleon segments and the telson and 

 uropods are missing; the head has also been slightly injured, and only one (right) of the 

 2nd gnathopods is present. There will be, however, no difficulty in recognizing the species. 



Genus Chosroes, Stebb. 

 Stebbing, 1888, p. 1208; 1906, p. 287. 

 Barnard, 1930, p. 369. 



To this hitherto monotypic genus can now be added a second species, which agrees 

 with the Challenger species in essentials, and also in possessing processes on the 2nd 

 joints of peraeopods 1 and 2, and excised margins of 2nd joints of peraeopods 3-5, but 

 is distinguished by an extraordinary development of dorsal keels which, on five of the 

 segments, end in forked teeth. 



Chosroes incisus, Stebb. 



Stebbing, 1888, p. 1209, pis. cxxxiv, cxxxv; 1906, p. 287. 

 Barnard, 1930, p. 369, fig. 38. 

 Schellenberg, 1931, p. 175. 



Occurrence: 1. St. 51. Falklands. 3 3$ 6-10 mm. 



2. St. WS72. Falklands. Many <?<?, ovig. $? and juv. up to ir mm. from sponges. 



3. St. WS92. Between Falklands and South America. 4 S3, 16 9?, 8 juv. up to 

 8 mm. from sponge. 



