118 Mr. W. Clark on the Muricidse. 



dots, lines or blotches. The branchial fold of the mantle extends 

 far beyond the short canal, and though cloven, forms apparently 

 an entire cylindrical tube, which is constantly in motion and used 

 as a tentacular organ. The head is pale red with a vertical 

 fissure, from which a long proboscidal trunk issues; the tenta- 

 cula are not long, but thickened from their bases to half the 

 length, at Avhich point the eyes are fixed at the internal angles, 

 from whence they terminate in slender conical points. The foot 

 anteriorly is truncate, indented in the centre in front, and curves 

 right and left into pointed auricles ; when extended it is longer 

 than the shell, and tapers posteriorly to a flat bevelled emai'gi- 

 nate terminus with scarcely a trace of caudal filament; the oper- 

 culum is corneous, of suboval shape, and shows the subungui- 

 culated stri« of increment. There are two semilunar branchial 

 leaves, one much larger than the other, with dark brown trans- 

 verse vessels, and connected with the mantle and neck in the 

 usual manner ; the heart is a pale, minute, subcircular inflation, 

 situate immediately behind the branchiae. The male has on the 

 right side the ordinary spatulate organe generateur, and the testis, 

 which is paler than the ovarimn, is substituted for that organ ; in 

 the female the ovariunr is large, of a deep marone red, mixed up 

 with the pale brown liver, and fills the three terminal volutions. 

 The animal displays very energetic locomotion ; it inhabits at 

 Exmouth abundantly all the sea zones. 



Murex varicoms, nobis. 

 Nassa varicosa, auctorum. 



This species has been considered a variety of the preceding ; 

 it is closely allied to it, but the animal and shell sufficiently in- 

 dicate specific distinction. To describe it in the entirety would be 

 a useless repetition, I therefore only note the deviations from its 

 congener : the animal is more slender and invariably of much 

 lighter colour, and in addition to the simple emarginate termi- 

 nation of the foot in the M. incrassatus, there are here two long, 

 pointed, apparently tentacular filaments issuing from the fillets 

 of the caudal fork ; these are the only two material difierences. 

 But in this case the shells of the two present so distinctive a con- 

 tour as to corroborate the malacological variations ; that of the 

 M. varicosus is of much more elegant form, being more produced, 

 the volutions rounder, with additional cancellated ribs, which are 

 not undated, and display the white varices, from two to five, of 

 former apertures, which in this species, in fine fresh specimens, 

 are of puqile colour ; but in the M. incrassatus the apertures are 

 rufous brown. This animal, at Exmouth, only inhabits the coral 

 zone, and is rarer by ten to one than the M. incrassatus ; it is 

 very lively and submits to the closest examination ; we have kept 



