I'KAliSOXlA. ^"^ 



frequently of a subtubular form, from the top of the peristome. 

 The shell has some resemblance to Rhiostoma, and still more to 

 Opisthoporus birostris." (Blanford.) 



170. Pearsonia minima, Godivin-Austen. 



Spiracnlum vwmmm, Godwin-Austen, Eec. Tud. Mus. viii, 1915, 

 p. 501, pi. 40, iig. 2. 



" Shell orbiculate, depressed, widely umbilicated. Sculpture, 

 fine transverse Hues of growth on the epidermis. Colour dull 

 ochraceous, with a green tinge, 3rd and last whorls crossed by 

 irregular broadish brown bands, indication of a band just below 

 the periphery. Spire depressed, but apex well above last whorl. 

 Suture impressed, the tube short, close behind the aperture, only 

 2 mm. distant. Whorls 4, regularly increasing. Aperture 

 circular, with very slight angulation at sutural margin. Peristome 

 double, both inner and outer lips continuous, moderately thickened 

 and slightlv reflected. 



" Major "diam. 9-2 ; alt. axis 3-25 mm." (Godiv in- Austen.) 



Nab. India: Jeku, Abor Hills (,/. Coggin Brown). 



" Lt. G. 1\ T. Oakes, E.E., has sent me seven examples of this 

 species from Sibbum, far finer in size; four are bleached. The 

 largest measures 10 mm. in major diameter. Three are perfect 

 with strong epidermis. Colour sienna-brown in tint \Mth ochra- 

 ceous mottling, with an indistinct peripheral band. Major diam. 

 11-5 mm. 



" This is a close ally of Spiraculum L-emjn, but the closely 

 mottled zig-zag pattern and black peripheral band is not seen in 

 that species ; in this respect it is similar to Spiracuhun nevilli of 

 the Dada Hills; it is smaller and rather flatter than that shell. 



" It is hardly possible to find better examples showing the deve- 

 lopment of the sutural tube in 6'inraculum than in the species 

 figured on plate xl. Althougli it is not from the Tsanspu A alley 

 but from the source of the Irrawady, Spiracidum piitaoeHsis has been 

 introduced in order to show how close is the relationship and how 

 beautiful evolutionary stages have been. In having a tube on 

 the suture behind the peristome and a simple peristome, both 

 belong to the genus Spiracidum. In figures 2 c and 3 6, within the 

 aperture may be seen the little orifice having a connection with 

 the branchial sac. In Spiramlum minimum this is very close to 

 the aperture, in Spiracidum putaoensis it is more remote. _ In the 

 first the inner and outer lips of the peristome are united and 

 thickened at the upper inner margin next the suture, while in 

 the second there is further development ; a clear separation of 

 the lips has taken place, the inner has a slight nick on tlie line of 

 the suture, shown by a sort of cicatrice up to the branchial 

 orifice, and the outer lip is expanded forward into a short scoop- 

 like process corresponding to the wing, as it has been called, 

 of Pteroojclos. The next species (fig. 4) [P. spirameniitm] might 



