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 three 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 dorsal 
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, directed 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 
