160 M. H. de Lacaze-Dutliiers 07i Phoeiiicurus. 



issuing from the buccal nerves and uniting them, passing in 

 front of the digestive tube. Was this an oesophageal collar 

 or a simple anastomosis ? 



Phoem'curus presents a very interesting histological consti- 

 tution, which will form the subject of a separate memoir. I 

 shall say but little about it at present. Its body has no general 

 cavity, it is therefore acmlomatous ; but it is filled up with a 

 cellular-fibrillar tissue showing nuclei, in the midst of which 

 and soldered to it are various organs and large cells or vesicles 

 which are often visible to the naked eye, and may acquire 

 enormous dimensions. 



Under the skin, after a layer of connective tissue, we find 

 long muscular bands regularly spaced and forming two 

 laminge, one dorsal, the other abdominal, passing to the buccal 

 and caudal extremities. Between these two laminae is the 

 central part. The body is in this way divided into three 

 zones, two external to the muscular bands and one interme- 

 diate. Further other fibres, also muscular, but transverse and 

 exterior to the former, to which they are attached, crossing 

 them at right angles, form a true trellis, which is easily dis- 

 covered ; for it appears very evidently so soon as one opens 

 the body of the animal and removes the integuments. At the 

 sides, to the right and left, there are also bundles of muscular 

 fibres passing perpendicularly from one surface to the other, 

 which assist in limiting the central space. 



It is in this median intermuscular space that we find the 

 digestive tube, the central nervous system, and a special gland, 

 the only organs that I have been able to observe. 



The digestive tube commences at the central orifice of the 

 pit noticed towards the rounded extremity, and descends to 

 the tail. Sometimes, after leaving the mouth, it presents a 

 dilatation followed by a constriction, indicated by l)elle Chiaje; 

 but great importance must not be attached to this arrange- 

 ment, which varies with the state of the individuals. 



The tube, which is sometimes even, sometimes irregular, 

 narrowed, or dilated, descends narrowing to the neighbourhood 

 of the tail, and throughout its length, as in all directions, in 

 front, behind, and on the sides, gives origin to branches, 

 which ramify infinitely, traversing the muscular interstices, 

 and extending by their delicate branches into the vicinity 

 of the integuments. From this point of view Phoenicxirus 

 is a very characteristic Dendroccelan. 



The walls of the digestive tube, which are of extreme deli- 

 cacy, easily escape observation if they are not filled witli some 

 coloured material or submitted to the action of some reagent 

 which reveals their presence. I have not found any anus. 



