. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 338 DISCOVERY REPORTS in Fig. 15. The integument overlying it shows the usual differentiation into cuticle and chitin (Fig. 15, cut. and chit.) and is not markedly developed to produce a lens-like formation. It appears to carry in life a violet-blue pigment similar to that noted by Kemp (19106, p. 644) in Systellaspis debilis, and which is found in the photophores of Decapoda generally (1910Z), p. 640). Underlying it the chitogenous epithelium is very thin for the most part and with only scatter
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 338 DISCOVERY REPORTS in Fig. 15. The integument overlying it shows the usual differentiation into cuticle and chitin (Fig. 15, cut. and chit.) and is not markedly developed to produce a lens-like formation. It appears to carry in life a violet-blue pigment similar to that noted by Kemp (19106, p. 644) in Systellaspis debilis, and which is found in the photophores of Decapoda generally (1910Z), p. 640). Underlying it the chitogenous epithelium is very thin for the most part and with only scattered nuclei. Here and there, however, occur closely packed groups of larger nuclei, one of which (Fig. 15, ) is found in the proximity of the photophore, but has no functional connexion with it. Its presence, however, may perhaps be taken as indicating that whatever the origin of the photophore it is not derived from the ectoderm. As in the previously described photophore (Fig. 14) the main mass of the organ consists of the photogenic cells in various stages of differentiation (Fig. 15, i, 2, 3, 4, and 5) and nuclei which probably belong to the reflector layer (Fig. 15, ). The reflector layer in all likelihood carries a red pigment similar to that found in HoplopJiorus novae-zealandiae (p. 336); this, together with the yellow colour which may be supposed to be associated with the actual photogenic cells, would give rise to the underlying shining orange-red pigment already mentioned (p. 337). Stages in the presumed growth and differentiation of photogenic cells are illustrated in detail in Fig. 16. On the extreme right of the figure at a is illustrated a photogenic nucleus (Fig. 16, n.) of the type found lying near the surface of the organ. It almost completely occupies a space bounded by a membrane which may reasonably be inter- preted as a cell membrane (Fig. 16, cm.), but no trace of cytoplasm has been found enclosed by it. The nucleus shows a reticula
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