LEPTON. 75 



malacological considerations, can belong to no other family 

 than the Arcadce. 



LEPTON, Turton. 

 L. SQUAMOSUM, Montagu. 



L. squamosum, Brit. Moll. ii. p. 98, pi. 36. f. 8, 9 ; and (animal) pi. O. 



f. 6. 

 Solen squamosus, Auct. 



Animal inhabiting a very flat, subrhomboidal, white, porcel- 

 lanous, punctured shell ; its ground colour is a clear white. 

 The mantle is very large, having the margins sinuated, often 

 puckered into two or three folds at the will of the animal ; 

 they extend beyond the shell more than one-third of the ver- 

 tical measure at its centre, from which springs a row, on each 

 side the middle of the ventral range, of twenty-five rather 

 long, slender, milk-white tentacular pointed filaments; but 

 the mantle thus clothed is only protruded largely beyond the 

 shell, from the middle of the anterior side, throughout the 

 ventral range, to the same level as the posterior end ; from 

 these points to the umbones it is never seen, being either 

 closed or not protruded, but its suture or edges are furnished 

 with about forty long, strong, blunt, frosted-white, rather 

 close-set cirrhi varying in length ; a part of these range at the 

 posterior side of the beaks, above the sessile anal orifice, which 

 occupies a small space without cirrhi, between the termination 

 of the protrusion of the margin and the commencement of the 

 larger filaments on the broader, larger, and posterior side ; of 

 that part of the filaments at the anterior side of the beaks, one 

 is thicker, broader at the base, and double the length of the 

 others ; this is the last of the larger ones, which at one time I 

 thought was tubular and might be an oviduct, but further 

 examination seemed to disprove this idea. None of the fila- 

 ments show much motion ; the long one only, when the animal 

 advanced a step, made an arcuated contraction, similar to that 

 of the fore-finger in extenso when quickly brought down to the 

 palm of the hand; it then resumed the straight position to 

 await another step : all the other cirrhi are either retractile or 

 contractile, separately or en masse. 



