ilOLLUSCA OF IXDIA. 211} 



Petalochlamys formosana var. hypograpta, Pils. <fe Hirase. 

 (Plate CXV. figs. 2-2b ; Plate CXVl. figs. 5-5 b.) 



Animal (figs. 2, 2 a). Foot long, not keeled, dark-coloured 

 towards the extremity, which is pointed, with a narrow linear 

 mucous gland ; the pedal margin pale, showing distinct from the 

 foot above, finely streaked ; the peripodial grooves close together, 

 forming a narrow band ; sole of foot with a central area. The 

 visceral sac specked black in front. 



The right shell-lobe broad, leaf-like, black with white venation 

 running from two branches to the edge ; the left shell-lobe broad, 

 slightly narrowing, with three or four parallel white veins running 

 from the edge of the mantle to the free end, throwing off minute 

 veinlets *. The right dorsal lobe spotted with black, the anterior 

 left dorsal lobe less so. The left dorsal lobe very small. 



The genitalia (fig. 5). There is no araatorial organ. The penis 

 is simple, the retractor muscle rising from the bend. The sperma- 

 theca was not seen in the first specimen dissected. The oviduct 

 long. 



The radula (fig. 5 a) has the formula 



+ 24 . 2 . 13 . 1 . 13 . 2 . 24-1- 



May be a few more laterals ; no row was quite perfect to the very 

 edge. The central tooth is tricuspid, also the admedian ; the laterals 

 are short, evenly bicuspid. 



The jaw (fig. 5 h) has a strong central projection. 



The buccal mass small, globose. 



This species has been described by Mr. Hirase, of Tokio, as a 

 Macroclilamys. A glance will show it has no affinity^ with that 

 genus, nor has it with forms such as Austenia, although the shell 

 is covered with broad lobes ; the genitalia are on quite a different 

 plan. The species nearest to it with which I am acquainted is 

 Belicarion ? willei/ana, from New Britain, described by me in the 

 Proceedings Malacol. Soc, April 1903, vol. v. p. 296, pi. ix. figs. 1-1 e. 

 Every character is the same in both. In the above paper I point out 

 how Helicarion idee differs from willeyana in the radula and foott. 



* These shell-lobes are quite separate the one from the other, not united as 

 in true Helicarion helence {vide Vol. I. Plate XLI. figs. 2-4). 



t I extract what I wrote in the above paper on pp. 297 & 298 : — 



P. 297. " Tlie interesting points in this species {H. uulleyana) are the great 

 length of the foot and the great expanse of the shell-lobes, with the conspicuous 

 central vein. The Drs. Sarasin, in their work, ' Die Land-Mollusken von 

 Celebes,' pi. xvii. fig. 149, show a somewhat similar veined structure in the large 

 right shell-lobe of Helicarion id<s. The radula is of a different tjpe, with multi- 

 serrated marginals, and the foot of the animal is widely different in form from 

 that of the present species ; so I think it safe to say, this New Britain form has 

 little relationship with that species." 



P. 298. "In this species the following characters may be noted: — (1) the 

 absence of the amatorial organ ; (2) the simple form of the penis, with no kalk- 

 sac or caecum at the retractor muscle ; (3) the very small number of teeth in 

 each row of the radula — that is to say, the radula is very narrow as compared 

 with that of some species of Helicarion. Thus far it agrees with Helicarion 

 permolle, Stoliczka, from Penang, and as regards cnaracters 1 and 2 with 



T 2 



