162 'I'HALKSSA. 



Suligeniis Thalessa, H. and A. Adams. 



P. HiPPOCASTANKUM, Lain. PI. 45, tig-s. 42, 48, 8»i to 41 ; PI. 4(;, 

 fig. 45. 



Yellowish or whitissli. moiv oi- less mottled or stained witli 

 dark chocolate, which is sometimes disposed in bands between 

 the spinose revolving ribs ; internally whitish with darker revolv- 

 ing bands. Sometimes the surface is nearly covered with black, 

 and a broad band margins the outer lip. Length, l'5-3 inches. 

 Philippines; Zanzibar ; Paumotus ; Ce-ntral Pacific ; 



Bay of Muscat ; [ndian Ocean. 



The description of Linnteus' P. hippocaafcmeum is too indett- 

 nite, and his references include other species ; so that I am com- 

 pelled to cite Lamarck. 



P. bifuierciUoris, Lam. (hg. oG), is merely a black variety, in 

 which the outer lip is generall}- broadly margined with black ; it 

 has no distinctive characters in the tuberculation. 



A similar form from the Red Sea has l>een called P. Savigiiyi 

 (tig. 45) by Deshayes. 



P. distinguenda, Dunker (tig. '61), is a depau|)erate fomn of the 

 black variety, the whorls merely nodulous instead of spinose. In 

 P. intermedia, Kiener (fig. 41), even the nodules have almost 

 disappeared and are principally indicated by white spots upon 

 the otherwise dark surface; P. oceUata^ Kiener (fig. 38), is the 

 young of this form. It may be convenient to designate P. inter- 

 media as a variety. Another variety is /'. alveolata, Reeve, 

 ■which I have also figured (fig. 40). It is whitish or brownish, 

 the tubercles darker; interior yellowish, mottled with brown. 



Length. 1*25 inches. 



Panama. (Cuming, i Forinosa ; Japan and ISwan River. 



(E. A.Smith.) 



P. TUMULOSA, Reeve. PI. 4G, figs. 44, 48. V.) ; PI. 46. figs. 33, 34 ; 

 PI. 47, fig. 65. 

 Revolving ribs rounded, raised into round nodules superiorly ; 

 outer lip thin, not dentate within. Color varying from ver}' 

 light brown to dark chocolate, moi'e or less mottled with white, 

 especially the tubercles. Length, 1-2 inches. 



Zanzibar? ; Japan. 



