Discovery reports (1957) Discovery reports discoveryreports28inst Year: 1957 66 DISCOVERY REPORTS of these apical spines. The outermost pair is extremely long, measuring rather more than one-third of the length of the telson, the next two pairs are progressively shorter and the inner two pairs are small and almost equal in length. Illig figures these spines as much smaller, the longest being less than one-fourth of the length of the telson, and he describes and figures three pairs of very small spines along the middle of the apex flanking the median spine, making six pairs in all. All these
Discovery reports (1957) Discovery reports discoveryreports28inst Year: 1957 66 DISCOVERY REPORTS of these apical spines. The outermost pair is extremely long, measuring rather more than one-third of the length of the telson, the next two pairs are progressively shorter and the inner two pairs are small and almost equal in length. Illig figures these spines as much smaller, the longest being less than one-fourth of the length of the telson, and he describes and figures three pairs of very small spines along the middle of the apex flanking the median spine, making six pairs in all. All these apical spines are finely spinulose in the Discovery specimen. Tattersall (1939, p. 230, text-fig. 3) referred an immature specimen of 7 mm., taken from of Seychelles, to this species. In his specimen the apex of the telson was truncate with no trace of emargination. It bore five pairs of spines like the Discovery specimen but the outer two pairs were almost equal in length, while the inner three pairs were all of equal length and very small with plumose setae in the spaces between them (Fig. 10). The Discovery specimen measures 9-6 mm. The brood lamellae are not yet developed and the differences it shows from Tattersall's smaller specimen and from the adult of Illig are due probably to growth changes. The eyes are well developed with normal ocelli and a golden brown pigment. They appear to be somewhat shorter and thicker than those figured by Illig. I am unable to make out the small finger-like process which Tattersall recorded on the inner face of the eye. Distribution. With the exception of the one record by Tattersall (1937, p. 1) from the Caribbean Sea, all records of this species are from deep water in the Indian Ocean near Aden or from the of Seychelles. The Discovery specimen was taken in much shallower water at a depth of 550-0 m., at station 1586 half-way between Seychelles and Obbia on the coast of Africa. Fig. 10. Petalophthalmus ocalatus Illig. Telson a
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