222 PSEUDOTROCHUS. 



f. 9; Conch. Icon., v, pi. 9, f. 28. PFB., Monogr., ii, 247; 

 iii, 479. MORELET, Ser. Conch., i, p. 21; Voy. Welwitsch, 

 p. 74. Perideris alabaster SHUTTL., Notitiae, p. 77. PFB., 

 Monogr., iv, 592; vi, 204; viii, 267; Novit. Conch., p. 314, 

 pi. 76, f. 2-5. SEMPER, Reisen im Archip. Phil., LandmolL, 

 p. 145, pi. 12, f. 1 (genitalia); pi. 16, f. 5 (radula). 

 KOBELT, Conchyl. Cab., p. 26, pi. 2, f . 2, 3 ; pi. 11, f . 5, 6.- 

 Achatina alabaster Rang, VIGNON, Bull. Soc. Malac. France, 

 v, p. 68, no. 29. CROSSE, J. de C., 1888, p. 301. 



The living animal is pale yellow or greenish, this color 

 showing more or less through the shell. It is long and slen- 

 der (70x5 mm.), with long tentacles. Rang has recorded 

 that it is ovoviparous. An individual was brought to him 

 containing 14 eggs and 10 young shells. The eggs are whit- 

 ish and oblong. Four young shells dried in a shell in our 

 collection measure 7 to 7.5 mm. long. They are very smooth, 

 thin and transparent, and angular at the periphery. In the 

 smallest one the axial chink is not quite closed. 



Rarely the yellow or brown cuticular bands are wanting. 

 The typical form of P. alabaster is rounded peripherally, 

 but it varies to forms with a more or less obvious peripheral 

 keel, and in these a white band usually underlies the cutic- 

 ular peripheral belt, or is exposed by loss of the latter, as 

 in the following species, which I believe to be merely an 

 extreme variation of the alabaster type. In fig. 72 a speci- 

 men is shown having the last whorl strongly angular in 

 front, rounded near the lip. PL 15, figs. 60, 61 represent 

 another shell in which the angle extends to the lip, though 

 obtuse there. Both of these are white-banded peripherally, 

 though with a yellowish band partly concealing the white. 

 In fig. 60 the slight columellar truncation has been over- 

 looked by the artist. 



P. alabaster is reported from Quicuje, in the district of 

 Loanda, on the mainland, by Morelet, from specimens col- 

 lected by Dr. Welwitsch. He thinks it may have been im- 

 ported there. 



