232 REPORT^— 1851. 



The PhyllodocidtB unquestionably live exclusively on animal matter. They 

 are always found near low-water mark, amongst corallines, sponges, minute 

 Actiniae, shelled Mollusca, and Cirrhipeds. Phyllodoce viridis prowls amidst 

 the small Cirrhipeds of our rocks, and is frequently found in companionship 

 with the LiniadcE. These worms may be frequently observed to thrust their 

 heads between the valves of the shells, protruding their proboscides to suck 

 up the juices of the defunct prey, for they seldom attack the living inhabitants. 

 In all the species of this genus the proboscis is constructed with express refer- 

 ence to the operation of sucking. This instrument, in these worms quite 

 ceaseless in its operation, is edentulous. It is gifted with no means of grasp- 

 ing, or cutting or piercing ; circumstances from which it may be reasonably 

 inferred that the food upon which the worms subsist must be so fluid as to 

 admit of being sucked into tlie oral orifice seated at the extremity of the 

 proboscis. This instrument in Phyllodoce viridis equals a fourth of the 

 body in length when fully extended. The surface, which is exterior when 

 protruded, is beset profusely with mammillary glandules raised above the 

 plane of the surface. Under the higher powers of the microscope these 

 glandules resolve themselves into minute Florence flask-shape involucra, 

 filled with spherical oleous cells, which, unlike ordinary oil-molecules, are 

 charged with brownish molecules surrounding a central nucleus. It is im- 

 possible to trace with the eye the presence of an excretory channel in the 

 axis of the flask. It is therefore probable that the secretion furnished by 

 these proboscidian papillae (as at 58), considerable in quantity, evidently 

 from their vast number, results from the successive bursting of the contained 

 cells ; those dehiscing first which are situated nearest to the attached extre- 

 mity of the gland. When withdrawn into the interior of the body, the pro- 

 boscis may be seen in an inverted position embraced by the oesophagus. It 

 may be here remarked, that in every Annelid in which a proboscis exists, the 

 process of withdrawing it into the interior of the body is as beautiful as it 

 is perfect in a mechanical sense. The jaws, when they are present, first 

 meet at the mid-point of the terminal orifice of the proboscis ; they are then 

 reversed, that is, their extremities are directed backwards towards the tail of 

 the animal : they may now be seen moving backwards in the axis of the 

 oesophagus as the act of withdrawing the proboscis proceeds. To explain 

 the mechanism of this movement, it is required only to conceive the exist- 

 ence of two concentric cylinders of longitudinal muscular fibres ; one on the 

 outside of the proboscis under the papillae, and the other on the inside be- 

 neath the mucous lining. It is now easy to perceive, that when the exterior 

 cylinder retracts, its muscles contracting, the effect on the proboscis will be 

 that of everting or protruding it ; and when, conversely, the interior cylinder 

 of muscular fibres diminishes its length (the muscles contracting^, the pro- 

 boscis will be furled upon itself, as it were, and drawn backwards into the 

 interior of the body. The orifice at the extremity of the organ, whether 

 guarded or not with jaws, is surrounded by a sphincter muscle, by which the 

 alimentary object is firmly grasped while being carried back into the oeso- 

 phagus during the inversion and retraction of the proboscis. These move- 

 ments may be readily imitated by the finger of a glove. It is a curious ana- 

 tomical fact, that the glandules furnishing the secretion, to the agency of 

 which the food is first submitted, should be restricted to the parietes of the 

 proboscis, since those of the oesophagus, properly so called, are generally 

 without a trace of them. Such glandular organization points to the pro- 

 boscis as the analogon of the mouth and pharynx, with their tributary glands 

 in the higher animals. For reasons, however, already advanced, it were 

 unsafe, on the ground of this apparent analogy, to rest the inference that 



