Plate 1 issued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1961, IX (1). [p.148, Fig. 109]. As Scottcalanus rotundatus.
Female (from Izu Region): a, habitus (dorsal); b, forehead (lateral); c, last thoracic segment and urosome (lateral, left side); d, rostrum; e, genital field; f, Mx1; g, P2; h, P3; i, P5.
- Head incompletely separates from the thopracic segments, as are the 4th from the 5th.
- Head without median crest.
- The rostral spine is about as long as the depth excavation.
- Abdomen about 5 times in the length of the cephalothorax.
- Urosome with 4 segments; segments and caudal ramus in the proportional lengths 46 : 20 : 14 : 5 : 51 = 100.
- Caudal rami about as long as wide.
- A1 23-segmented, extends to the end of the caudal rami.
- Exopod of A2 1.3 times as long as the endopod.

Male: j, last thoracic segment and urosome (lateral; k, distal segments of left P5.
- Lateral corner of the last thoracic segment narrowly rounded at the azpical portion.
- Urosomal segments and caudal ramus in the proportional lengths 19 : 25 : 21 : 19 : 8 : 8 = 100.
- A1 20 segments, segments 8-13 fused, 24 and 25 well separated.
- Exopod of A2 1.5 times long as the endopod.
- Md with a robust 2nd basal segment and a narrow biting part. Maxillae and Mxp as those of the female.
- P1 to P4 as those of the female.
- The 1st segment of the exopod of the right P5 has a small process on the distal inner margin. The distal segment of the exopod of the left P5 has a pad of stiff hairs and 2 strong curved spines (fig. k).

Plate 2 issued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1961, IX (1). [p.149]. As Scottcalanus rotundatus.
Female: Segments of A1 in the proportional lengths.

Plate 3 issued from : O. Tanaka in Publ. Seto Mar. Biol. Lab., 1961, IX (1). [p.149]. As Scottcalanus rotundatus.
Male: Segments of A1 in the proportional lengths.