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On A New Species of NEAERA.
by Rev. J. E. TENISON-WOODS, F.G.S., &c., Corr. Mem. Linn. Soc., N.S.W.
Read on 30 July 1877
The following species of the rather uncommon genus Neaera was dredged up a few days ago, by Dr. James Cox, in Port Jackson, at a depth of 16 fathoms. Only three or four specimens were obtained, in company with a number of broken and dead valves of Trigonia Strangei. It is worthy of remark that the number of Neaera properly so called is far less numerous than is commonly imagined. Many shells formerly belonging to this genus have been distributed among other tribes. See A. Adams on the Neaera of Japan, Ann. Nat. Hist., 1864, p. 206. Two species were formerly attributed to Australia, N. fragilis, A. Adams, and N. rugata, the former from Moreton Bay, the latter Port Jackson. N. fragilis is now removed to the genus Theora. N. rugata is a very small species. The following is the diagnosis.
NEAERA LATESULCATA, n. s., N. t., fragili, ovali, ventricosa, antics latiore, rotundata, obtuse angulata, postice valde rostrata, albida, opaca, concentrice sulcata et plicata, plicis, 12-16, latis, planatis, superne angulatis et subacutis, aetate latioribus, supra rostrum prolongatis, sinu postico deflexis, deinde tenuiter curvatis, saepe autem
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confluentibus; rostro compresso, rotundato, vix recurvo, a margine postico sinu lato, angulato, sejuncto, superne ab umbonibus irregulariter crebre transversim corrugato; lunula longa, angusta, lanceolata, parum impressa; umbonibus parvis, incurvatis; pagina interna lactea, nitente corrugata; impres. musc. magnis sat conspicuis; fossa ligamenti, cochleariformi, prominenti. Long, 13, Lat. 22, alt. 9, long. rost. 7, lat. (circiter) 4, mill.
Shell fragile, oval, ventricose, anteriorly wider, rounded, obtusely angular; posterior with a long rostrum; milky white, opaque, concentrically sulcate and plicate, plaits 12 to 16, broad, flattened, angular above and subacute, becoming wider with age, prolonged upon the rostrum, deflected by a posterior sinus, then slightly curved, and often confluent; rostrum compressed, rounded, slightly re-curved, separated by a wide angular sinus, the upper part closely transversely corrugate from the umbones to the end; lunule long, narrow, lanceolate, slightly impressed; umbones small, incurved; interior dull milky white, shining, corrugate; muscular impressions large, rather conspicuous, ligamental fossa spoon shaped and prominent.
This singular species is mainly remarkable for its broad corrugations, which show inside the valves, and for the singular sinus at the rostrum, where the plaits become straightened out, and either parallel or confluent, following the marginal side of the prolongation on whose upper side, fine striae (which continue to the umbone) are given off at right angles to the axis. These striae seem to agglutinate to themselves fine particles of sand, &c. The shell is somewhat like the British N. cuspidata, Olivi, but differs in the corrugations, the peculiar marks on the rostrum and the sinus, which in the species referred to is double. Theora fragilis has no proper rostrum, and is pellucid. N. rugata is finely striate on both rostrum and shell. There are some mesozoic fossil forms somewhat like the new species. Neaera is a genus which has been existing from the Oolitic period, since when it has been gradually increasing in number.