46 NUCULID^. 



(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. 1-30. — T. conspicue obliqua, 

 latitudine lougitudinem sequante, compressa, cute luteo-castanea 

 induta, haud radiata, sublfevigata. Margo dorsalis anticus arcuatus, 

 elongatus. Latus posticum fere nullum, interne acclivitate repeu- 

 tina marginis veutralis muitum arcuati et argute crenulati oblique 

 escisum. Lunula valde prominens, bene definita. — Peculiarly 

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

 glossy, yellowish-chestnut epidermis, not colour-rayed, everywhere 

 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 sciircely any, obliquely cut otf below by the abrupt 

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

 lated within : lunular region peculiarly prominent and well defined. 

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



6. N. NiTiDULA, A. Adams, f. 142. — T. obhqua, ovato-conoi- 

 dalis, Eeque lata ac longa, haud ventricosa, valde infequilateralis ; 

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

 undique laevis. Margo ventrahs crenulatus, valde arcuatus, postice 

 conspicue acclivis. Latus auticum rotundato-subcuneifomie. Nates 

 prominentes. Lunula subangulatim definita, muitum 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, subaugularly defined. 



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

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

 aceo-cinerea induta, nonnunquam lineis fumosis radiata, rugis 

 subpliciformibus concentricis striisque radiantibus subobsoletis 



