236 REPORT— 1851. 



remark which does not fall under the description already presented. The 

 intestine is of a bright yellow as far as the tail. The colour of the biliary 

 yellow pigment of the intestinal parietes blending with the dull white of the 

 integument, these worms appear as yellowish-white threads, twisting about 

 with great beauty. They are distinguished, like the Spios, by the fact that 

 the whole of the posterior three-fourths, or more, of the body hangs on, like 

 a lifeless coil of sand, to the cephalic and only active and locomotive part 

 of the body. The former is apparently dragged along by the latter in pro- 

 gression. Although supplied with feet and branchiae, they seem in this 

 region to take little part in the movements of the anterior part of the body. 

 This incapacity for muscular movement seems to depend upon the weight 

 of the earthy mass contained in the intestine. The blood being brightly red, 

 the branchiae form a pleasing contrast with the dark colour of the body; 

 These worms live on sand, and are destitute of proboscis. The head is 

 prolonged into a finely tapering snout, by means of which its march through 

 the sand is eflPected with tolerable facility. 



The preceding description will serve to convey a pretty exact idea of the 

 character of the alimentary canal in the Opheliadce — worms which are not 

 uncommon on the British coasts. The author recently made several additions 

 of species to the list of British Ariciadce ; they are distinguished from 

 the old species by a shorter body, by the presence at various points of fila- 

 mentary appendages, not unlike those of Cirrhatulus, by a far greater activity 

 in the posterior parts of the body in progression, and by the absence of the 

 earthy colour, and undue accumulation in the posterior moiety of the digestive 

 canal. 



Cirrhatulus Lamarckii, so abundant between tide-marks on the coast of 

 Swansea, subsists almost entirely by swallowing clay. Its long branchial 

 appendages are little subservient to, and less used for the prehension of food. 

 The mouth, a small circular orifice, is ventrally situated, and some little way 

 posterior to the tapering snout, in which the head terminates: it is well 

 adapted for sucking in semi-solid food. The pharynx is susceptible of ever- 

 sion in a slight degree. The native colours of this worm are beautifiully 

 variegated : the brilliant yellow of the intestine, which begins near the head 

 and continues to the tail, relieved by the greenish hue of the integuments of 

 the back, contrasts agreeably with the vermilion thread which spangles 

 every portion of the worm. The alimentary canal, from one end to the other, 

 is closely united, at short intervals, by means of minute septal bridles, to the 

 integuments ; the peritoneal fluid, on that account, is very limited in quantity. 

 The course of the intestine describes a zigzag from one extreme to the other. 

 The oesophagus is short, and the proboscis wanting. The biliary glandular 

 layer of the intestine is thick and flocculent, and densely supplied with blood. 

 This worm is capable of throwing out from the general cutaneous surface a 

 considerable amount of viscid adhesive secretion, which enables the worm to 

 roll itself in an impenetrable coat of mail. The mechanical act of applying 

 the surrounding substances to the body is accomplished by the thready 

 appendages. Nothing can be more exquisite than the perfect and yet rapid 

 manner in which these microscopic strings perform this work of protection. 

 In its natural state Cirrhatulus does not inhabit channels. It is commonly 

 found in soft semi-fluid clay, stretched under stones near the ebb-mark of 

 the tide. 



The family of Aphroditacece are uniformly proboscidean. Many mem- 

 bers are found in deep water, rendering it dilRcult to assign their exact 

 habitation. The Polynoe are inhabitants of the shores, and affect pro* 

 tected situations, such as the inferior surface of slates and stones, over the 



