26 



DISCOVERY REPORTS 



SECOND CALYPTOPIS 



The average lengths and ranges of length for varying numbers of 2nd Calyptopis are 

 stated in Table IX. The range of forty-eight larvae, the largest number measured in one 

 sample, is between 2-38 and 2-96 mm. and the average is 2-71 mm. The smallest larva 

 measured was 2-13 mm. and the largest 3-33 mm. 



The carapace is evenly rounded and there are no lateral denticles (Figs. 5 a, b). The 

 abdomen is segmented, and in lateral view the developing uropods can be seen within 

 the integument. The telson (Fig. 5 c) is furnished with three postero-lateral spines on 



Fig. 5. Second Calyptopis. 



a, dorsal aspect ( x ig); 



b, lateral aspect ( x 25); 



c, telson ( X 80) ; 



d, antennule ( x 80) ; 



e, masticatory lobes of the first maxilla ( x 287). 



each side of the seven terminal spines. A spine is situated laterally on each side of the 

 telson, as in the ist Calyptopis. Both lateral and postero-lateral spines carry a diminutive 

 dorsal spinule just beyond the middle of their length, as described by Rustad in 

 Euphausia frigida. Posterior to the ist pair of thoracic appendages are situated ventrally 

 and side by side two roughly hemispherical lobes enclosed by the integument containing 

 the buds of the following five pairs of thoracic legs. These lobes are a distinguishing 

 feature of the 2nd Calyptopis of E. superba, and their presence is, of course, associated 

 with the exceptionally early development of the thoracic appendages II-VI in this 



