SYSTEMATIC REPORT 65 



finally, by the armature of the telson. In H. fyllae, the proximal two-thirds or more of the lateral 

 margins are unarmed and the distal third is armed with only three, or occasionally four, long spines 

 on each side with small spines in the spaces between them. In H. falklandica the lateral margins are 

 armed along the distal four-fifths of their length with spines in series and there may be seven or 

 eight very long spines with smaller ones between them on each side. The armature of the distal fourth 

 of the telson in the two species is almost identical. 



Distribution. Of the eighteen stations at which this species has been taken, sixteen are situated 

 around the Falkland Isles. It was not until after I had described and named the species, that I re- 

 ceived a further instalment of material and found that it had been taken also at two stations in the 

 Magellan Strait. The material is not in very good condition and it has not been easy to find perfect 

 specimens. Although the types, from which the details of the appendages are taken, came from 

 station WS 213, the drawing of the adult female (Fig. 9 A) is reconstructed from specimens from sta- 

 tions WS 214 and WS 229. The majority of the animals occurred at depths ranging from around 200 m. 

 to about 400 m. Only at station WS 749, where two fragments were taken at a depth of 4o(-o) m. 

 were any captures made at a depth of less than 195 m. The greatest depth at which they were taken 

 was 403-430 m. at station WS 839. 



Genus Petalophthalmus W.-Suhm, 1875 

 1875 Petalophthalmus W.-Suhm, p. 23. 



Remarks. The name of this genus is derived from the peculiar leaf-like form of the eyes in the 

 type species, P. armiger. A second species, P. oculatus, in which the eyes are better developed with 

 functioning ocelli has since been added to the genus. The most outstanding character of the genus is 

 the long, very powerful, prehensile mandibular palp. 



Petalophthalmus oculatus Illig, 1906 



(Fig. 10) 

 1906 a Petalophthalmus oculatus Illig, p. 194, figs. 

 1930 Petalophthalmus oculatus, Illig, p. 411, text-figs. 

 1939 Petalophthalmus oculatus, Tattersall, p. 229, fig. 



Occurrence : 

 St. 1586. 2. v. 35 (night). North-west of Seychelles Is. 550-0 m., 1 $ imm., 9-6 mm. 



Remarks. This is the only species of the genus, or indeed of the family at present known, in which 

 normal functioning eyes are present. It was founded by Illig for a single female specimen of 18 mm. 

 with well-developed marsupium, captured in 1200 m. near Aden. Though it is by no means adult 

 I have no hesitation in referring this specimen taken by 'Discovery' II to this species. It agrees 

 very closely with the description and figures given by Illig as regards general form, the shape of the 

 rostrum and carapace, the form of the antennal scale, the uropods and the telson. Such variations 

 as it shows in armature may be attributed to its immaturity. 



The apex of the telson is emarginate as shown by Illig, the spines arming the lateral margins are 

 fewer and confined to the distal half of the telson leaving the proximal half of the margin naked. In 

 Illig's specimen there were seventeen spines evenly spaced along the whole margin on each side, but 

 in the Discovery specimen there are only seven. The apex is armed with five pairs of spines on each 

 side and a strong median spine. There are also two pairs of long plumose setae with somewhat bulbous 

 bases borne in the spaces between the median spine and the innermost spines and between these and 

 the next pair. The main difference between this specimen and Illig's lies in the number and length 



