20S ME, STANLEY W. KEMP — BISCAYAN PLANKTON : 



The rostrum is very slender and nearly as long as, or rather longer than, the carapace ; 

 it bears a blunt spine at its base immediately over the posterior edge of the orbit. The 

 carapace is rather less than twice as long as broad ; it is provided with a blunt spine in 

 the mid-dorsal line near the hinder margin, and occasionally with two or three extremely 

 minute spinules on the postei'ioi';vbasal edge ; the orbital angle is obtuse and rounded, 

 the antero-lateral angle is produced forwards as a long, slender, upcurved spine. 



The 3rd abdominal somite is deep, dorsally rounded in side view, and produced 

 posteriorly in the form of a hood over the 4th somite. The 6th somite is not marked 

 off from the telson ; the two together are about four times the length of the 5th somite. 

 The telson (fig. 18) is wide, rather deeply emarginate apically, and is furnished on each 

 side with eight seta3. The uropods are not free, but in some of the specimens, which are 

 evidently about to moult, they may easily be seen lying within the telson (fig. 19) ; in 

 these cases the telson itself is retracted somewhat from the outer edge, a fine filament 

 extending from it down each seta. 



The eye (fig. 14) is about as long as the carapace, and is widest across the cornea ; the 

 latter is black and hemispherical, and is composed of approximately 200 to 300 facets. 



Eight pairs of limbs are present, the antennules, tlie antennae, the mandibles, two pairs 

 of maxillae, and three pairs of maxillipedes. No pereiopods are developed in this stage, 

 but one or two pairs may be represented by, buds. 



The antennules (fig. 2) reach slightly beyond the eyes ; tlie peduncle is in some cases 

 two-jointed, in others, in which development has proceeded somewhat, three-jointed. The 

 basal joint is long and shows no trace of the lateral process. The outer flagellum is 

 rather stout, not longer than the ultimate peduncular segment, and is furnished with a 

 few setae at its apex. The inner flagellum is represented merely by a rounded boss 

 bearing a stout plumose seta of varying length. 



The antennae (fig. 11) scarcely reach to the end of the antennular peduncle ; the 

 single basal joint is as long and as wide as the scale, the latter being elliptical in shape 

 and provided with 10 to 15 finely plumose setae ; the distal spine is not present, and the 

 extreme apex is divided by two or three faint transverse articulations. The distal end 

 of the basal segment bears on its inner side a stout seta rather longer than the scale ; 

 this doubtless functions as a flagellum. 



The mandibles (fig. 3) show no trace of a palp, distally they are almost squarely truncate 

 and are provided with a few minute teeth. The 1st maxilla (fig. 4) consists of the two 

 basal lobes and an endopod. The lower lobe is rounded acd furnished with about six setae, 

 the upper rather longer with a narrow truncate apex armed with a few short bristles. 

 The endopod bears two setae at about the middle of its internal margin and four at the 

 apex. The 2nd maxilla (fig. 5) is widest basally, the internal margin is four-lobed, each 

 lobe being provided with nvtmerous setae ; the endopod also bears several setse, while 

 the oval exopod, which reaches to about half the length of the palp, is furnished with 

 five setae. 



by sets of characters by whicli they may be readily recognized. The term has no special significance, nor is it 

 possible, in the present species, to say how many moults are included in each. 



