CAMPONTIA. 



171 



inarticulate, setaceous, originating in the front margin. Mouth with 

 a pair of exsertile, corneous, brown, hooked mandibles, which, when 

 in motion, it is seen incessantly to protrude and retract ; no pro- 

 boscis. On the front and ventral margin of the first segment are two 

 short unjointed legs, armed with a circle of retractile claws ; and the 

 last segment is furnished, near its termination, with two similar legs : 

 the other segments are footless and naked; 

 but a few hairs terminate the anal segment. No. XLVII. 



which is very slightly lobate. Anus round, Campontia eruciformis. 

 simple, small. 



This animal lives among Confervse, in pools 

 left by the tide ; and is very common in Ber- 

 wick Bay. It moves with considerable quick- 

 ness by means of its mandibles and legs ; for 

 the former seem to be as subservient to pro- 

 gressive motion as the latter ; and, during its 

 progress, the upper lip is considerably pro- 

 truded, as shown in No. XLVII. c. Within 

 the first segment we observe a heart-shaped 

 lobated organ, which, although colourless and 

 almost transparent, is undoubtedly the sto- 

 mach. The very short gullet enters it above ; 

 and from its inferior end a small intestine pro- 

 ceeds, which suddenly enlarges at the com- 

 mencement of the fourth ring, and continues 

 of the same calibre to its termination at the 

 anus. This large intestine is always filled 

 with earthy feculent matter, except that por- 

 tion of it which traverses the last three seg- 

 ments, and which is usually empty. Two 

 slender thread-like vessels are to be traced 

 winding down the sides in the space between the skin and intestine ; 

 these occasionally anastomose by still slenderer transverse branches ; 

 but I could not discover any common centre of departure. At the 

 end of the ninth ring there are four filiform, dark-coloured, tubular 

 organs, which seem to originate in the sides of the intestine : they 

 traverse the ninth and a part of the tenth segment, and end appa- 

 rently with free extremities. These are probably hepatic vessels ; 

 and the deficiency of solid feculent matter in the intestine, below 

 their origin, appears to prove their importance and adaptation to 

 the proper assimilation of the food. 



When I first described this animal, its close resemblance to some 

 caterpillars was particularly mentioned, and, indeed, suggested the 

 name. That it was actually a larva I was unsuspicious, for I be- 

 lieved it to be an established fact among entomologists that no insect 

 passed its preparatory stages in sea-water. I was however informed, 

 soon after the publication of the genus, that Mr. MacLeay had 

 proved that our worm was the larva, probably, of some dipterous fly ; 

 but in what way this conclusion had been arrived at was not 

 stated. Mr. Green thinks that he has confirmed its truth {Charles- 



a. Natural size. b. Mag- 

 nified, c. The head, 

 slightly compressed 

 between plates of 

 glass, d. The under 

 side of the anal seg- 

 ment. 



