Mr. W. Clark on the Muricidse. 125 



Another variation from the M. gracilis is, that the foot when 

 fully extended is as long as the shell ; it is bordered with flake- 

 white spots ; but no pink marks are mixed up with it either be- 

 low or above, as in M. gracilis. In this species the only pink or 

 red spots are on the termination of the branchial fold. The 

 organe generateur is of a pea-green coloux', and in other respects 

 is precisely similar to that of the type. 



Murex costatus, IMontagu et nobis. 

 Pleurotoma costatum, auctorum. 



Animal spiral, of seven or eight turns, nearly throughout of 

 a pale hyaline ethereal blue, shaded with the most delicate 

 white ; the mantle is of the general ground colour, and even with 

 the shell, except the slight depm-atoiy fold which lies in the 

 minute canal at the upper angle of the outer lip, and the 

 branchial fold that lines the basal canal and floats far beyond it : 

 we have omitted to state that the prevailing ground colour is 

 sprinkled with minute sulphur-yellow flakes. The head is small, 

 compressed, almost obsolete, and from the vertical fissure under 

 it the usual anned proboscis is exserted. The tentacula are mode- 

 rately long, with eyes placed externally on ofi^sets half their length; 

 the terminal portions are slender, setose and slightly clavate at 

 the tips. The branchiae and other organs offer no variations. 

 The foot is pale ethereal blue, with a transparently white nar- 

 row border, in front truncate, slightly indented, and gently 

 curves at the right and left angles into small auricles, narrow, 

 and tapers to a point which extends beyond the spire. 



This minute species displays, in its splendid coloration of 

 azui'e shot with brilliant snow-white streams, and in the propor- 

 tions of its organs, more deviation than is usually exhibited in 

 this beautiful group, but these elegant distinctions are only spe- 

 cialties. Its habitat extends throughout all the zones. I have 

 had only one opportunity of examining this beautiful minute 

 creature, which being lively, degage, and free from shyness, gave 

 me every assistance, and the mate of this lovely Venus may truly 

 apply to it the O vidian phrase, " non rustica conjux." The 

 Scotch specimens are of larger growth than those of more south- 

 ern climes. — Exmouth, 20th August 1850. I have just met in 

 the littoral zone with sevei'al live animals, and I find that in the 

 males the organ of reproduction is exactly the same as in the 

 type. 



Murex purpureus, Mont, et nobis. 



Pleurotoma purpureum, auctorum. 



I can only from recollection speak of this species ; I examined 

 several of the animals many years ago, but I have not the notes 



