REPORT ON THE SCHIZOPODA. 156 



somewhat shorter than the rest. Beneath the outer integument can be faintly traced at 

 the base of the telson two oval plates, the budding uropoda. 



The cellular masses, representing the compound eyes, are somewhat more distinctly 

 defined, and exhibit the fascicle of luminous fibres unaltered, whereas in the anterior 

 part a small pigmentary spot has appeared, the first trace of the ocular pigment. 



The antennulfe (fig. 21) have now become divided into a cylindrical, triarticulate 

 peduncle, and two rudimentary flagella, the outer of which represents the terminal joint 

 of the antennulse in the preceding stage, whereas the much smaller inner flagellum has 

 appeared in the pi-esent stage. 



In the structure of the other limbs no difi'erence can be observed from that in the 

 preceding stage. 



Third Calyptopis Stage (figs. 23-26). — This stage corresponds very nearly mth the 

 earliest stage of Euphausia, as figured by Professor Claus. The animal measures 

 2 '20 mm. in length, and has (see fig. 23) the tail still more developed, appreciably 

 exceeding the carapace in length. 



The eyes, still completely covered over by the hood-lihe anterior expansion of the 

 carapace, are almost globular, and exhibit, besides a somewhat more extensive 

 accumulation of pigment, also the first faint trace of \dsual elements. 



The antennulge (fig. 24) are more powerfully developed, and from the outer corner of the 

 basal joint juts forth a strong, anteriorly pointing spine, denticulate along the inner edge. 



The other limbs belonging to the anterior division have remained nearly unaltered, 

 with this exception, that the outer masticatory lobe of the first pair of maxillae (fig. 25 ) 

 has a greater number of spines, viz., five. 



At the base of the telson (see fig. 26) the uropoda have developed, luit are still very 

 small and without any marginal setaj, exhibiting, however, their two terminal plates 

 though not yet defined from the basal part. Of these, the outer is much the larger, and 

 juts out at the end exteriorly as a strong spine, whereas the inner plate is veiy small 

 and merely papillar in form. 



No trace whatever either of legs or pleopoda can as yet be detected. 



Of the inner organs in this and the preceding stages but little can of course be 

 observed in the spirit-specimens. Having, however, thoroughly examined in this respect 

 corresponding stages of the northern species, Nyctiphanes norvegica (M. Sars), in a living- 

 state, I am enabled to confirm the correctness of the statements respecting the inner 

 organisation of the larvae given l3y Professor Claus in his a])ove quoted treatise. 



Development of Euphausia pellucida, Dana (Pis. XXIX., XXX.). 



Of this form, the most frequent of aU the Challenger Euphausiidse, numerous larva' 

 in difl^erent stages of development were found in the surface-gatherings sent me for 



