LARVAE OF SERGESTES 21 



Pleopods 2-5 with rudiments of endopods. Uropod with bare part a httle shorter 

 than setose part, and ten times as long as wide. 



Stage I differs only from stage 2 in size (3-6 mm.; rostrum 1-48 mm.), smallness of 

 pleopods and form of antenna (fig. 12/). The latter has a long flagellum (2-15 mm.) 

 with a pair of very small spines near the base and another pair on the penultimate 

 segment. A rudiment of the mandibular palp is present. 



Mastigopus I (Fig. 12 d, e). Length 5-1 mm. Rostrum 0-99 mm. 



Carapace with very small supraorbital and long hepatic spines. Posterior dorsal spine 

 minute. 



Abdominal somites with very minute dorsal spines on somites 1-3, those of 4-6 long 

 and nearly equal. Pleura with small points. Telson zh times as long as wide, with distal 

 fork, each arm bearing a small inner and an outer spine ; there is also a pair of small 

 spines just in front of the fork. 



Eye one-quarter length of body, of same shape as in Acanthosoma. Flagellum of 

 antenna 16 mm., without kink and without curved setae. Mandibular palp small, two- 

 segmented, with three apical setae. Legs with trace of exopods. Uropod seven times 

 as long as wide, the bare part about equal to the setose part. Pleopods very long, 

 2-4 with small endopods without setae : endopod of pleopod 5 long, setose. 



Sergestes tenuiremis Kroyer 



Hansen, 1922, p. 86, Mastigopus; p. 89, Acanthosoma. 

 Gurney, 1924^, p. 88, fig. 2, Elaphocaris 2. 



Material. This species was not common at Bermuda, and it has not been identified 

 in the Discovery material. A mouh was obtained from Elaphocaris 3 to Acanthosoma, 

 but the cast skin was very fragmentary. It was, however, quite clear that the Elaphocaris 

 was of the hispida type. We have no doubt that the two stages described belong to this 

 species, partly by reason of the agreement in colour between them and the Acanthosoma, 

 and partly because we have identified with reasonable certainty the only other forms of 

 this type as belonging to S. crassus and S. robustiis. 



Description. Elaphocaris 2 (Fig. 13 a). Length i-6 mm. Rostrum i-i2 mm. 



Rostrum, lateral and dorsal processes simple, very long, and with numerous spinules, 

 the lateral processes curving backwards. Telson arms long and slender. Eye short; 

 eyeball large and asymmetrical. 



Elaphocaris 3 (Fig. 13 b). Length i-8 mm. Rostrum i-i2 mm. 



Carapace with long supraorbital spines, and a pair of very small spines behind them 

 and in front of the very small dorsal organ. Lateral processes very long, the spinules at 

 their base in front longer than the rest, and recalling the " epaulette " found in S. robustus. 

 Posterior process very long. Abdominal somites with small lateral spines. Telson arms 

 long and slender. 



Eyes on slender stalks, the eyeball large and asymmetrical, the greatest width nearly 



equal to total length of eye. 



