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Art. LI.—Three New Tertiary Shells.
[Read before the Philosophical Institute of Canterbury, 3rd August, 1904.]
Plate XLIV.
Pleurotoma hamiltoni. XLIV., fig. 1.
Shell elongato-fusiform, large, aperture occupying nearly half the length of the shell. No longitudinal ornamentation; whorls keeled. Spire long and sharp, of 10–11 whorls, the whorls shouldered, and ornamented below the shoulder with fine spiral striæ, more distinct in the upper than in the lower whorls. The shoulder of the upper 8 whorls with small tubercles, about 12 in a whorl. Suture with a row of raised points formed by the growth-lines. Spirals below the sinus 6 on the 7th whorl, 12 on the 9th whorl. Body-whorl nearly smooth, the spiral striæ being obsolete or altogether absent. Aperture narrow with a well-marked posterior, wide sinus, not very deep, rather broad, and not separated from the suture. Anterior canal long and straight.
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Length, 120 mm.; width, 30 mm.; length of aperture, 54 mm.
Locality.—Waihao Forks. Collected by Mr. Harold Hamilton.
The type is in the Canterbury Museum.
Mitra hectori. Plate XLIV., fig. 2.
Shell elongato-fusiform, the aperture about as long as the spire. Pullus conical. Whorls of the spire 7 (not counting the pullus), nearly flat, separated by a channelled suture, with a rounded shoulder; smooth; ornamented with 3 distant, low, very obscure spiral ribs. Body-whorl with a low obscure spiral rib near the shoulder, and distinctly spirally ribbed at the base, the central portion smooth and rather flattened. Aperture narrow, outer lip thin; columella with 4 well-marked plaits, of which the posterior is rather the largest. There are no longitudinal striæ.
Length, 45 mm.; width, 13 mm.; length of aperture, 22 mm.
Locality.—Waihao, near the coal-mine. Collected by Mr. Aug. Hamilton.
The type is in the Canterbury Museum.
Pecten hilli. Plate XLIV., fig. 3.
Large, equivalve, rather compressed, equilateral, suborbicular. Ears large, equal, without any sinus; the posterior with 3, the anterior with 4 slightly undulating ribs. Right valve with about 30 narrow ribs, many of which are grooved in the ventral half of the shell, and slightly roughened by growth-lines. Interstices broader than the ribs, smooth, simple. The left valve is imperfectly preserved, but what can be seen of it does not differ much from the right valve.
Length, 4–55 in. (116 mm.); height, 4–25 in. (108 mm.); thickness, 1–55 in. (40 mm.).
Locality.—Napier, in limestone.
Allied to P. triphooki, but distinguished from that species by the narrower and more numerous ribs, which are not so scaly, as well as by the simple interstices.
The type is in the Canterbury Museum.
Explanation of Plate XLIV.
| Fig. 1. |
Pleurotoma hamiltoni, Waihao Forks. |
| Fig. 2. |
Mitra hectort, Waihao, near the coal-mine. |
| Fig. 3. |
Pecten hillt, Napier. |