EEPORT ON THE PYCNOGONIDA. 



125 



of the legs, always been considered as a very important support for the beliel m the 

 near relationship between the Pycnogonida and the Arachnida, and more especiaUy 

 the Phalaugida. 



MorphologicaUy, the oesophagus extends from the mouth to behind the oesophageal 

 commissures. Taking the function of the organs into consideration, I beUeve that only an 

 extremely smaU part should bear the name of oesophagus. At a very short cUstance from 

 the mouth the oesophagus widens considerably. This '^ddened part, which shows its 

 greatest dilatation in front of the midcUe of the proboscis, slopes again backwards, and 

 imperceptibly passes over into a much narrower canal, which extends immediately 

 behind the oesophageal commissures. The widened part of the oesophagus, which ahnost 

 reaches to the end of the proboscis, is invested by a chitinous wall. This wall is beauti- 

 fuUy beset with thin paraUel chitinous bands, which are furnished with numerous thin 

 spines. In the front part these are wanting. They begin on the two ventral parts of the 

 inside a little before they are found on the dorsal part. These foremost spines have the 

 form of short teeth, and only further back do they assume the form of long thin spines 

 or needles. From the wall of this part of the oesophagus numerous bundles of trans- 

 versely striated muscles extend till they reach the outer wall of the proboscis, their 

 distribution being in Nymphon, e.g., such that two longitudinal rows are attached 

 to each of the three parts of which the inner waU of the oesophagus is composed 

 (PI. XVIII. fig. 9). As to the function of this part of the oesophagus, judging from 

 these muscles and from its internal armature, I think it not very hazardous to com- 

 pare it with the cardiac portion of the stomach of the Crayfish. It is a masticating 



apparatus. 



Posteriorly it passes over into a very long (slender species of Nymphon), or rather 

 short {Colossendeis) cylindrical tube, the wall of which is still divided into three longi- 

 tudinal parts, which on a transverse section are triangular and leave an extremely narrow 

 canal in their midcUe. I stucUed the histological structure of this part of the wall, which 

 extends to beyond the oesophageal commissures. Its cells are of a long cyhncbical form, 

 longer in the middle and shorter on both sides of the triangular part. They are fui-nished 

 with distinct nuclei, which sometimes are all placed near the outwardly dii-ected extremity 

 of these cells, but sometimes also are found more in the middle. Between these cylin- 

 drical cells there are some of a long conical shape, the base of the cones being, as a rule, 

 directed outwards. Inside, the surface of these cells is invested by a structureless membrana 

 intima, and outside a similar cuticular formation is present (PI. XXI. fig. 6). This 

 epithelial covering does not end abruptly immediately behind the oesophageal commissures. 

 In the interior of the succeeding part of the intestine it forms three glandular bodies, 

 which hitherto have not been observed, and whose function, judging from their position, 

 must be, I believe, pancreatic. In fig. 7 on Plate XXI. I show the place occupied by these 

 glands, and in fig. 8 of the same plate a transverse section near the extremity of the two 



