Miscellaneous. 297 



and of a triangular form ; the part of the body which extends 

 before it may be regarded as a cephalic lobe. The eyes are wanting; 

 but there exists on each side, about the level of the mouth, a vibra- 

 tile pit of oval form, and of which the greater axis is vertical. These 

 pits, the immediate neighbourhood of the mouth, and a small part 

 of the posterior extremity are the only exterior parts of the body 

 which present vibratile cilia. By this character the Polygordii are 

 removed from the Nemertians, in the same manner as they are 

 removed from the Annelides by the complete absence of locomotive 

 setae. 



The cuticle is thick, and presents, as in the greater part of the 

 Annelida, a double system of stria? distinctly inclined to one another ; 

 and at the interlacing of a great number of these we see the orifice 

 of a tube perforating the cuticle, and which is only the excretory 

 tube, of small clear glands of diverse forms, and situated in the sub- 

 jacent layer corresponding to the hypoderm of tho Annelida. In 

 transverse sections the striated cuticle seems to be formed of a 

 number of superimposed layers. The hypoderm, besides the glands 

 which it contains, is clearly decomposable into beautiful polyhedric 

 nucleated cells. Below the hypoderm there is a layer of trans- 

 verse muscles, of which the perfectly distinct annular fibres are dis- 

 posed in a single plane. According to Schneider, this layer is absent 

 in the Polygordii that he examined ; and it is on this fact that 

 he bases the approximation that he has proposed between Polygordius 

 and the Nematoids. Beneath the muscular layer the longitudinal 

 muscles are found disposed in thin radiating lamellae, stretching 

 almost to the intestine, and in no point resembling the muscular 

 bundles of the greater part of the Annelida and Lumbrici. In this 

 there is, in fact, something which slightly reminds us of what is 

 seen in several Nematodes ; but this is the only point of resemblance 

 that it is possible to find between the animals now under considera- 

 tion and the parasitic worms. In a transverse section we see all 

 along the median ventral line a thickening, which at first seems to 

 be continuous with the hypoderm, but which a more minute analysis 

 shows to have a more complex constitution. I have reasons for 

 believing that this is the nervous system ; but it is a point that 

 requires further investigation. From the summit of this thickening 

 two partitions, symmetrical with respect to the vertical plane, start 

 obliquely, inclined eighty degrees to each other, and ending laterally 

 at the integuments. These partitions extend through all the extent 

 of the ring ; and as another vertical partition binds the intestine to 

 the integuments along the median dorsal line, the general cavity is 

 divided more or less completely into four longitudinal chambers. 

 Transverse vertical partitions also divide it into rings completely 

 separated from one another, and identical with the rings of the 

 Annelida. 



The digestive tube presents no special glandular appendages ; it has 

 neither trunk nor gizzard, only in the neighbourhood of the mouth 

 two lateral longitudinal folds playing the part of lips. It is con- 

 stricted in passing through the interannular partitions, so as to 



