MOLLUSCA OF INDIA. 289 



is of tlie same dark colour, probably a very dark gi'ey in life ; tbe 

 left dorsal lobe is faintly papillate and closely mottled black. The 

 peripodial margin is streaked with black, giving it the same fringed 

 appearance as is seen in A. gigns. The keel of the foot is very 

 sharp and continuous to the posterior side of the visceral mass. 

 There is no V-shaped depression so tvpical of true Girasia, vide 

 Plate LV. figs. 1, 1 a, 1 b, and Plate LIX. figs. 1 , 1 a, 1 6, & 2, 2 a; 

 and this species must be placed in Austenia on the ground of the 

 form of the animal being more important than the form of the 

 shell, although in the more fully developed sliell-lobes it shows au 

 approach to Girasia. The mucous gland is linear ; the foot has a 

 central area. 



Length of the animal 48 mm. 



The different parts of the generative organs were so hard and 

 pressed together that it was most difficult to extract them entire ; 

 the amatorial organ is 23 mm. long and cylindrical, the sperma- 

 theca very long, and on the whole the genitalia are similar to 

 those of A. gigas. 



The male organ displayed the position of a spermatophore 

 passing down it to the generative aperture (fig. 1 c), and lying 

 within the sheath ; showing clearly that the flume is the first part 

 to be extruded. 



The spermatheca contained some five spermatopliores (fig. 1 d) ; 

 they were much pressed and agglutinated together, so that only 

 by patient soaking was it possible to disentangle them ; they 

 resemble my description and drawings of this organ of the type 

 species of 'G. hool-eri, Yol. I. p. 220 ; P. Z. S. 1880, pi. xxvi. 

 figs. 8, 8 a ; A'ol. II. Plate LXXXVIII. figs. 1, 1 a. The capsule 

 is about 12 mm. in length, the flume about 6 mm. The position 

 of the spiny plumes is at the base of the capsule, none were se(Mr 

 at the base of the flume as in 31anaila, Vol. II. Plate XCIII. 

 fig. lb, -p. 114. 



The jaw (fig. 1 a) differs much from that of A. gigas, being 

 much straighter in front and not so solid, it is thin and trans- 

 parent. 



The radula (fig. 1 b) is interesting from the great number of 

 teeth in the row. It is 6-25 mm. in length and 3'5 mm. in 

 breadth, and was got out entire. There are 145 rows of teeth, 

 and tbe formula is 



104 . 1 . 22 . 1 . 22 . 1 . 104 

 or 127 . 1 . 127. 



The central and admedians are elongate on rather narrow plates, 

 the latter with a small cusp low down on the outside, at the 

 22nd tooth this cusp is larger and at the 23rd is higher, until at 

 the 24th the tooth is nearly evenly bicuspid, and this shape is 

 continued to the margin. It will be seen that in respect to the 

 number of admedian teeth, the formula agrees with that of 

 A. gigas ; in total number there are some 60 more, and the lateral 

 teeth are more uniform in shape. 



2b2 



