Issued from : R.B. Seymour Sewell
in Scient. Rep. John Murray Exped., 1947, 8 (1). [p.244, Fig. 67].
Male (from Arabian Sea): A, A1 of left side; B, A2; C, Md palp and base of biting ramus of right side; D, curved process on posterior lip of mouth; E, Mx1; F, Mx2; G, P1; H, P3; I, right P5; J, left P5.
Nota: - The posterior thoracic segment ixs produced backwards in a wing, the apex of which is rounded and bears a minute hair or seta.
- A2 : the proportional lengths of the exopod and endopod are as 53 to 47.
- Md asymmetrical; on the right side the biting ramus is produced on its anterior,aspect in a long curved tooth, similar to that in the female
H. attenuatus; in association with this tooth there is a curved tongue-like process from the lateral lip of the mouth on the right side. Sars (1925, Pl CXVI, fig.8) has described and figured a similar projection in
H. attenuatus, but he states that it situated on the left side (probably an error, fot it seems that the hook-like tooth on the mandible and the palp-like process are in apposition with each other). In the left Md the biting ramus (= gnathobase) bears a series of 5 teeth and 1 seta; the 1st tooth is simple; the 2nd is bifid but has a straight posterior margin; the 3rd, 4th and 5th are bifid atb their extremities and their posterior edges are armed with a row of spines. The basal segment of the palp bears 1 seta; the endopod arises from the segment considerably distal to the origin of the exopod (as in
H. acutilobatus).
- Mx1 closely resembles that of the female of
H. acutilobus except that the seta arising from the 2nd outer lobe is small.
- Mx2 with the 1st lobe bearing 2 groups of setae; in the 1st group are 2 setae, the distal of which is minute; in the 2nd group are 4 setae, of which the 1st is much smaller than the others. The 2nd lobe bears 1 seta. The 3rd lobe has 2, and the 4th lobe, 3 setae. The 5th lobe bears 6 setae, of which 4 are serrated, and the 6th is a stout curved spine with a few teeth on its margin. The 1st and 2nd segments of the endopod bear 2 setae, 1 short and curvee and the other straight; both are serrated along one margin. The 3rd segment bears 3 straight, serrated setae.
- Mxp resemble that of
H. acutilobus.
- P1 endopod 3-segmented, whereas in the females of both
H. attenuatus and
H. acutilobus there are only 2. Sars neither describes nor figures P1 in the male of
H. acutilobus, but, as he makes no mention of any difference, it is to be presumed that in that species the endopod resembles that of the female and is composed of 2 segments only.
- P2 to P4, both rami composed of 3 segments. The 3rd segment of the exopod shows a slight difference from the condition seen in
H. acutilobus female. The distal marginal spine, instead of being situated at the external distal angle, arises from the outer margin at a point about 1/3 the length of the segment. The external marginal spines arising from exopod 1 and 2 are much longer than in
H. acutilobus female.
- P5 symmetrical; exopod composed of 3 segments, of which the 1st and 2nd each bear 1 marginal spine and the 3rd segment bears 2 marginal spines and 1 terminal spine.. There are no setae on the inner margin of any of the segment. The endopod is composed from 3 segments, of which the 1st and 2nd are devoid of a seta and the 3rd segment bears 4 setae.