l22 CYCl.OPllORIDjE. 



be placed in this genus and is a true link witli it. The tube is so far 

 forward, it still forms a part of the peristome, a complete isolated 

 orifice has not yet been formed^ — -it is a slit; the process of its 

 further development would be the growing more forward of the 

 whorl itself. In fig. 5, Sinraculum lai/orensis, we find this stage 

 reached, and in fig. 5 b the inteiual oritice has been left behind, and 

 externally a perfect tube is seen on the suture (fig. 5 rt) behind the 

 aperture and completely separate from it. While this evolution 

 has been in progress, another change has taken place; the scoop 

 in fig. 4 has grown forward considerably into the elongated gutter 

 of fig. 5, with its edges growing inwards and nearly touching, 

 corresponding in life, in all probability, with a sharp fold of the 

 mantle edge, which with further growth might become more and 

 more tube-like." {Godwin-Austen.) 



171. Pearsonia nagaensis, Godwin-Austen 6f Beddome. 



Spirnculum nagaense, Godwin-Austen & Beddome, A.M. N. H. 



ser. G, xiii, 1894, p. 509. 

 Spiraculnm (s. sir.) nagneuse, Kobelt & Mollendorff, Nachr. Deuts. 



Malak. Ges. xxix, 1897, p. 135; id., Cat. Pueuni. 1809, p. 103. 

 Pearsonia {Pearsonia) ncu/aoisis, Kobelt, Das Tierreicli, Lief. 16, 



1902, p. 174. 

 Pearsonia nagaensis, Kobelt, Concli.-Cab., Cvclophoridae, ii, 1911, 



p. 771, pi. 113, tigs. 12, 13. 



Original description: — "Shell discoidal, upper surface flat, 

 widely umbilicated; sculpture, strong longitudinal striation, covered 

 with a thick epidermis, with two parallel bands of close set hairs 

 on the periphery. Colour umber, with a series of darker bands 

 crossing tlie whorls. Spire quite flat; suture deep, the sutural 

 tube is 4'5 mm. behind the peristome, is well developed, arched 

 and bending over, and lies directed backwards and parallel with 

 the suture; wliorls 5, rounded, the last descending very sliglitly ; 

 aperture circular ; peristome thickened, white, continuous, with an 

 angulate notch above and close to the body-whorl ; operculum 

 widely spiral, shelly, wliitish grey. 



" Maj. diaui. 17'5, min. l4"0 ; alt. axis 5*2.5 mm."' {Godwin- 

 Austen 1^- Beddome.) 



Hah. India :Maokokchung, Naga Hills {Maspratt). 



" This small form may be distinguished from ^S'. hisjndum, var. 

 minor, of Teria Ghat in the Khasi Hills and base of the Dafla 

 Hills, in the I'orm and direction in which the sutural tube lies 

 backward on the shell ; in hispidum it lies across and nearly at 

 right angles with the suture, in this new form it is on the line of 

 the suture." {Godwin- Austen Sf Beddome.) 



172. Pearsonia nevilli, Godwin- Austen. 



Spiraculam nevilli, Godwin-Austen, J. A. S. B. xlv, part 2, 1876, 

 p. 174, pi. 7, fig. 2. 



