IIUTHVENIA. ;*1 



half the size, colour more brown ; the spiral liraa are absent, save 

 for a faint trace above the suture of a single one, and the costae 

 almost obsolete ; the armature appears to be very similar, save that 

 the palatal denticles are only three or four in number." (Sykes.) 

 The parietal armature consists of two simple, sub vertical plates 

 which are somewhat thickened and truncate at the lower, and 

 attenuated at the upper extremities ; these plates are separated by a 

 distance of a quarter of a whorl, and the posterior one is the stronger 

 (see fig. 9 rf, which shows the parietal wall with its two plates). 



Fig. 9. Ruthvcnia caliglnosa. 



The palatal armature is in two vertical series : the anterior series 

 consists of an obliquely ascending short quadrate tooth near the 

 periphery, and below this an obliquely descending lamelliforin 

 tooth, with a slight, horizontally elongated denticle below its 

 posterior extremity ; the posterior series is similar to the anterior 

 one, but the teeth are stronger and thicker in the former, while 

 there is in addition a horizontally elongated denticle on the 

 anterior side of the upper tooth. The specimen shown in 

 fig. 9 o-c measures 6 millimetres in diameter, alt. 3 millimetres, 

 and is in the collection of Mr. Ponsonby. The armatures are 

 figured from the type-specimen in the collection of Mr. Sykes, who 

 kindly permitted me to open the shell for the examination of the 

 armature. 



48. Ruthvenia biciliata, Pfeiffer. 



Helix bidliata, Pfeiffer, P. Z. S. 1855, p. 112; Hanley & Theobald, 



Conch. Ind. 1875, pi. 159, figs. 1 & 4. 

 Nanina (Hemiplecta) biciliata, Pfeiffer, Malak. Blatt. ii, 185(5, 



p. 121. 

 Macroclilamys biciliata, Pfeifter & Clessin, Nomencl. Ilelic. Viv. 



1881, p. 45. 

 Nanina (Kaliellci) biciliata, Tryon, Man. Conch, ser. 2, ii, 1880, 



p. 67, pi. 28, figs. 7 & 8. 

 Plectopylis (Sykesia) bicilata, Sykes, Proc. Malac. Soc. London, iii. 



1898, pp. 66 & 160; Glide, Science Gossip, N. s. vi, 1899, p. 1(5, 



fig. 99 (shell and armature). 

 Sykesia biciliata, Godwin- Austen, Moll. India, ii, 1907, p. 19(5, 



pi. 112, fig. 3 (anatomy). 



