Mr. E. A. Smith on the Genus Planaxis. 37 



frontals. One prse- and one postocular. Six upper labials, 

 the third and fourth of which enter the orbit, and are much 

 larger than the anterior and posterior pairs. Temporals 1 or 

 2 + 3, all small, scale-like, the anterior in contact with the 

 postocular, fourth and fifth labials, but not with the occipital. 

 Lower labials small, the anterior in contact with each other 

 in front of the chin-shields, which do not enter the labial 

 margin. 



The single specimen known is 13 inches long, the tail being 

 one inch. It is not known from Avhich part of Africa it was 

 obtained. 



III. — A List of Species of the Genus Planaxis, ivitk Descrip- 

 tions of eleven new Species. By Edgar A. Smith, Zoological 

 Department, British Museum. 



The genus Planaxis was founded by Lamarck in 1822, in the 

 '■ Hist, des Anim. sans Vert.' vol. vii. p. 50, to include a group 

 of shells generally of a somewhat ovate-conical form, more or 

 less transversely sulcated, and having for the generic character 

 the columella provided with a callosity at the upper part, ab- 

 ruptly truncated at the base, and forming with the outer lip 

 a small basal channel. 



Only two species (which I now unite) were known to La- 

 marck ; but since then the number has greatly increased, and 

 now forty-four distinct forms have been described, and un- 

 fortunately several of them more than once by various authors 

 under different names, as will be observed from the following 

 list. 



1. Planaxis sulcatus. B.M. 



A dark fuscous-coloured species, sparingly dotted with 

 squarish white spots, strongly spirally ribbed and lirate 

 within the outer lip. 



Buccinum sulcatum, Bom, Mus. Yindob. p. 258, pi. 10. f. 5, 6. 

 Planaxis bticctnoides, Deshayes, Anim. s. Vert. ed. 2, vol. ix. p. 237. 



Var. a. Shell elongate, acuminate ; spiral ribs ornamented 

 with equal-sized black and white squarish spots. 

 Planaxis sulcata, Lamarck, /. c. p. 236. 



Var. b. Shell shorter ; black spots flowing into irregular 

 longitudinal stripes. 



JBucci?mm pt/ramidale, Gmelin, Syst. Nat. p. 3488. 

 Planaxis vndiilata, Lamarck, /. c. p. 236, 



Hob. Australia, Philippines, Mauritius, S. Africa. 



