108 APHRODITACE^. 



each side ; these are similar in structure, and jointed only at the 

 base: scales naked, 12 placed over every alternate segment, so that 

 the 1 2th is on the 23rd ; if there are more scales, the succeeding are 

 on every third segment: feet well-developed, biramous, but the 

 branches are almost connate, furnished with two fascicles of bristles, 

 the superior in a spreading tuft, the inferior in a flattish brush, a 

 spine to each fascicle : bristles simple, stout, the superior tapered to 

 a serrulate point ; the inferior with a claw-like point, and flattened 

 underneath on one side of the shaft, where it is roughened with 

 spinous denticles in close-set transverse series : anal segment with 

 styles. 



Lepidonotus is readily distinguished from Aphrodita by the num- 

 ber of the antennae, by the more powerful armature of the mouth, 

 and by the part of the body at which the scales cease to alternate 

 with the cirri. The form of the body, and the number of its com- 

 ponent rings, vary much ; all our known native species are linear 

 or elliptic-oblong, but there are foreign species of a linear and worm- 

 like figure. The back is either entirely covered with the scales, or 

 naked in the middle, the scales in the latter being less developed and 

 not meeting on the mesial line. 



The head of the Lepidonoti is large and corneous, with four eyes on 

 its upper convex surface arranged in pairs : the antennae are rarely 

 two only, three being the usual number, of which the central one is 

 longer than the lateral, and it again yields in strength and longitude 

 to the palpi. The mouth has a projectile proboscis, with a circle of 

 little tentacula round its orifice, and four large horny jaws curved at 

 their points. The scales or elytra are always exposed, and are very 

 variable in number, but the first twelve pairs regularly alternate with 

 the superior cirri on the first twenty-three segments, and if more 

 elytra exist, they alternate in a different series, or on every third 

 segment : they are lamellar or sometimes vesicular, and either smooth 

 or covered with little granulations. The branchiae, which are simple 

 and obscure, exist only on the non-elytrous feet, and follow conse- 

 quently the same alternating order. The feet are bifid, but the 

 superior branch is small and almost confluent with the inferior, which 

 is greatly developed. The superior cirri are long, the inferior short 

 and conical : the bristles of the superior branch short, and almost 

 always slenderer than those of the inferior, subulate and smooth at 

 the point, or like the inferior bristles, somewhat thickened and 

 serrulate along the edge. The spines present no peculiarity. The 

 first pair of feet are destitute of bristles, but are terminated by two long 

 tentacular cirri, which advance on each side of the head and resem- 

 ble antennae ; while on the last segment we find filiform appendages 

 formed by a nutation of the superior cirri, and constituting in general 

 terminal styles. 



The Lepidonoti are carnivorous. They prey on living inverte- 

 brates ; and the strong do not hesitate to kill and eat the weaker of 

 their own and alUed species. They live in obscurity on rocky shores. 



