538 Dr. F. A. Bather — The Mount Torlesse Annelid. 



The association of Mr. Alexander M'Kay's name witli this species 

 requires no justification, as this is one of the rare cases in which 

 the adoption of a personal name conveys a meaning which is not 

 misleading. 



Holotype: Specimen No. 24 of Mr. Ferrar's list (Fig. 1). Nos. 17, 

 18, 19, and 21 also belong to this species. 



Horizon : Probably not below Upper Carboniferous and not above 

 Trias (see Von Haast, 1887). 



Localities : Ashley Gorge (holotype), Mueller Glacier, Mt. Torlesse, 

 and many other places in New Zealand, especially Hutt and Selwyn 

 counties (see Hector, 1885 and 1892). 



THE CURVED FORM. (Figs. 4-7.) 



This has not hitherto been described. It is represented by 

 specimens 22 and 23, both collected by Captain Hutton. No. 22, 

 from the Kowai Eiver, is a water-worn pebble from which one 

 quarter has been broken away. The substance of the pebble is 

 a very hard dark-grey shale, weathered greenish. It is 19 ram. 

 thick, 80 mm. long, and 63 mm. wide. On one of the flat surfaces, 

 occupying an area about 52 mm. long x 50 mm. wide, are the 

 remains of nineteen individuals, of which the most complete measures 

 19-3 mm. along the chord of the curve (Fig. 4). No. 23, from the 

 Wilberforce River, is a fragment of hard black shale, iron-stained, 

 slightly contorted, slickensided at one end, and with numerous 

 cracks filled with silica. It is 14 mm. thick, 96 mm. long, and 

 about 40 mm. wide. One flat surface is slightly water-worn and 

 displays the remains of three individuals, of which the most 

 complete measures 28-5 mm. along the chord of the curve (Fig. 7). 

 In both specimens the substance of the fossils is silicified. 



The above numbers suggest that these animals were more 

 gregarious than Torlessia Mackaijt. 



In No. 22 the shells lie in all positions : most are in the plane 

 of bedding, either on their sides, or with the concave curve up, 

 or with it down; a few, of which only a ti'ansverse section is 

 seen, appear to lie at an angle to the plane of bedding. Those 

 which lie in the bedding-plane are compressed, and the side that 

 happens to lie uppermost is usually pressed inwards so as to make 

 the transverse section approach a semicircle or even a crescent. 

 That this is an effect of pressure is further shown by the fact 

 that the transverse sections mentioned above are more circular in 

 outline. 



The individual, 19*3 mm. long, on specimen 22, lies on its side, 

 having the uppermost side crushed in, as above described, over 

 the middle of its course, but partly broken away at the ends. 

 The larger, convex curve has a radius of 12 mm. (a trifle over 

 that of a shilling). The smaller, concave curve has a radius of 

 about 7'6 mm., but is not so nearly a segment of a true circle. 

 The outside diameter of the tube at a little distance from the 

 larger end is about 4-3 mm., but since this end is broken, the 

 diameter at the wider aperture cannot have been less than 5 '3 mm., 



