NEMATOSCELIS MICROPS. 291 



though the specimen is only 3.2 mm., thus as long as the intermediate Furcilia- 

 stage of Nyctiphanes; it may be added that the thoracic legs are also somewhat 

 more developed than in the last Furcilia-stage of Nyctiphanes measuring 3.7 

 mm. Fig. 4b shows that the telson tapers gradually to the insertion of the outer 

 pair of postero-lateral spines, that the intermediate pair of these spines are very 

 slender, the inner pair somewhat strong with the fine denticles along their inner 

 margin, while the telson itself is produced in an acute spine and the terminal 

 spines are wanting. 



A specimen in the intermediate Furcilia-stage (from the "Siboga") is 

 2.7 mm. long; its pleopods are developed about as in the same stage of Nycti- 

 phanes, while its antennular flagella and two anterior pairs of thoracic legs are 

 a little more developed than in the latter form. But the telson is quite different, 

 as to shape of itself and relative size of the three pairs of postero-lateral pairs 

 similar not to the first but to the last Furcilia-stage of Nyctiphanes, while the 

 terminal transverse margin of telson is short with only thi*ee small spines. 



Nematoscelis microps G. O. Sars. 

 Plate 12, figs. 5a-5c. 



Last Furcilia-Stage. — The frontal plate is very long, linguiform, longitudi- 

 nally somewhat excavated, anteriorly broadly rounded at the sides and at the 

 middle produced in a very small, tooth-shaped rostrum (fig. 5b); the dor.sal 

 keel of the carapace is long and high, oblong-triangular, with the upper angle 

 rounded and the front margin rather steep, situated a little nearer to the posterior 

 margin than to the rostrum; the tooth on the lateral margins of the carapace 

 is very large, du-ected much downwards and originating at the posterior margin 

 (fig. 5a). 



The eyes have the lower section rather well developed, but the upper section 

 is very small. — The antennular peduncles are rather slender; the process from 

 the first joint does not reach the end of second joint, which is a little more than 

 twice as long as thick and conspicuously shorter and thicker than the third; the 

 flagella are very short, unjointed; the lower with a single terminal seta (omitted 

 in the figures) . — Antennae and maxillipeds completely larval in shape and 

 tegumental surface; the exopod of the maxillipeds a little longer than the endo- 

 pod. — First thoracic legs somewhat developed; the endopod reaches slightly in 

 front of the end of rostrum, has the full number of joints with last joint termi- 

 nating in a few spines; a branchial lobe is visible. — Second thoracic legs rather 

 small, with the endopod scarcely twice as long as the exopod and the branchia 



