OBSEEVED AT MOGADOK. 183 



An attentive study of all these shells together toith their animals 

 and hahits in their native haimts, may possibly lead to a diiferent 

 conclusion. But my present impression, from a long and careful 

 scrutiny of nearly 200 Mogadorian examples of the shells alone, is, 

 that they are all merely varieties or forms of a single highly poly- 

 morphous species. 



The streaky longitudinal, instead of spiral, arrangement of the 

 coloured markings, when any are discernible, seems to be charac- 

 teristic. Only in one example of (3, 2 b, exhibiting a near approach 

 to Chemnitz's figures 2078, 2079, do the colours assume a fasciated 

 disposition, forming a tolerably distinct bluish band along the 

 infra-sutural depression, with two or three more indistinct subcon- 

 fluent brown bands below. This singular example bears, indeed, 

 a most marvellous resemblance, both in shape and colour, to 

 J3iiccinum vittatum, L., for which, on a cursory glance, it might 

 easily be mistaken. 



All these shells are apt to be coated with a thick greenish in- 

 crustation. 



Melanopsis prwrosa (lJ).=^Buccinum prcerosum, Linn. Syst. ed. 

 ]2. 1203, originally found along with M. cariosa, a 1 supra, by 

 Alstromer in the aqueduct at Seville, figured in Hanley, Conch. 

 Linn. t. ii. f. 5, from an authentic specimen, and by Chemn. xi. 

 285, t. 210. f. 2080, 2081, from examples collected in stagnant 

 pools and streams in Morocco, should be searched for at Mogador. 

 It is distinguished from M. cariosa, /3 2 {Mel. hticcinoidea, Per., 

 laevigata, Lam.), by the volutions being tabellated or retuse at the 

 top next the suture (" anfractibus supra planis," Chemn. I. c.), each 

 thus appearing partly sunk or immersed (intrusus) in the lower 

 one preceding. 



I forbear recording as a Mogadorian species from a single worn 

 and bleached example from Mrs. Elton's collection a shell which, 

 though in shape and general aspect much resembling some narrow 

 elongated forms of 31. cariosa, /3 2J, yet dififers specifically in the 

 apertiire being simply ovate or acute at top, not acuminate or 

 produced into a sort of constricted narrow channel ; and in its 

 coloration, which consists of fine close-set regularly equidistant 

 spiral brown or chestnut lines or strise, instead of longitudinal 

 irregular streaks, interrupted in the specimen, owing to its worn 

 condition, on a polished ivory-wliite or yellowish-white ground. 

 It appears to be a dead and thickened worn example of the W. 

 Indian (Jamaican) Melanopsis lineolata (Gray) ; and it may there- 

 fore be suspected to have become mixed up accidentally with 



