150 NUCULIDJE. 



(the beaks being almost terminal in the adult), and less prominent 

 behind. More or less compressed, and under a not quite dull 

 epidermis, that ranges in tint from olivaceous-yellow in the young 

 to deep-olive in the mature, colour-rayed ; rays for the most part 

 narrow and smoke-coloured, sometimes (especially in the young) 

 orange-red, and broader ; sometimes painted with both colours. 

 The lunule is elongated, but less prominent than in nucleus.- — 

 There is more posterior projection in the fry, but at that stage the 

 elongated shape is peculiarly conspicuous and the rays more vivid. 



5. N. castanea, A. Adams, f. 130. — T. conspicue obliqua, 

 latitudine longitudinern sequante, compressa, cute luteo-castanea 

 induta, baud radiata, sublaavigata. Margo dorsalis anticus arcuatus, 

 elongatus. Latus posticum fere nullum, inferne acclivitate repen- 

 tiua marginis ventralis multum arcuati et argute crenulati oblique 

 excisum. Lunula valde promineus, bene definita.— Peculiarly 

 oblique, about as broad as long, compressed, invested with a rather 

 glossy, yellowish-chestnut epidermis, not colour- rayed, every w here 

 almost smooth, merely obscurely wrinkled concentrically, devoid 

 of radiating or divergent sculpture. Anterior extremity narrowed, 

 yet well rounded ; front dorsal edge peculiarly elongated and arched. 

 Posterior side scarcely any, obliquely cut off below by the abrupt 

 ascent of the much arcuated ventral margin, which is finely crenu- 

 lated within : lunular region peculiarly prominent and well defined. 

 — Mr. Cuming and Mr. Metcalfe each possess a single specimen. 



6. N. nitidula, A. Adams, f. 142. — T. obliqua, ovato-conoi- 

 dalis, reque lata ac longa, baud ventricosa, valde insequilateralis ; 

 cute polita pallide olivacea, zonisque nigro-cinereis cincta, induta, 

 undique laevis. Margo ventralis crenulatus, valde arcuatus, postice 

 conspicue acclivis. Latus auticum rotundato-subcuneiforme. Nates 

 prominentes. Lunula subangulatim definita, multum eminens. — 

 Oblique, ovate-conoidal, as broad as long, by no means ventricose, 

 extremely inequilateral, with a polished pale olive-coloured epi- 

 dermis, and dark grey zones, everywhere smooth. Ventral mar- 

 gin crenulated within, much arcuated, rising behind so as to 

 obliquely round off the posterior corner. Extremity of the sub- 

 cuneiform anterior side rounded, front dorsal slope very decided, 

 much produced. Beaks acute, prominent, touching. Lunular 

 area much projecting, subangularly defined. 



7. N. nitida, Sowb., f. 120. — T. ovato-trigona, satis ventri- 

 cosa (in exemplis junioribus compressa), cute nitidissima oliv- 

 aceo-cinerea induta, nonuunquam lineis fumosis radiata, rugis 

 subpliciformibus concentricis striisque radiantibus subobsoletis 



