212 Dr. A. Korotneff on Poljparmm ambulans. 



the supporting lamella, and therefore can conduct no further 

 unless we assume that the impressions received maj be trans- 

 ferred to the supporting lamella itself, which is perhaps 

 capable of contraction, or perhaps rather to its cells. The 

 sense-cells occur most numerously upon the acetabula, and 

 are particularly observable in their inner inflation. This 

 arrangement seems to indicate that, in creeping, Polyparium 

 feels the surface of the supporting object so as to seek out a 

 definite course. 



The nuclei which occur in such quantities among the 

 ectodermal cells belong chiefly not to the fibrillar elements, 

 but to small embryonal cells {em. z), which are very nume- 

 rous, and in this case, where there is no. special nerve-layer, 

 may also perform the function of nerve-cells. Besides the 

 gland- and sense- cells the so-called support-cells may also 

 possibly occur ; but I could not distinguish them from the 

 other elements. 



From this description the acetabula of Polypariuin are 

 certainly of primitive structure, inasmuch as they possess no 

 true musculature ; but they must be regarded as the first stage 

 of an adhesive apparatus, and not merely as inflated portions 

 of the wall. Although the acetabula of the foot have no 

 immediate relation to muscles, this by no means excludes the 

 possibility of an indirect relation ; as we shall soon see, there 

 are, in the interior of the body, special muscles which serve 

 only to pull away the acetabula from the surface of adhesion. 

 The supporting lamella of the foot is remarkable for its con- 

 siderable development. 



The entoderm possesses special villiform outgrowths which 

 project into the interior of the body. The interior, or, in 

 other words^ the lumen, is here, as already stated, clavate in 

 form and occupies the whole acetabulum, and may receive 

 the name of the stomach (PL XIII. fig. 2, Mg.) ; the occur- 

 rence of entodermal villi shows that assimilation takes place 

 here more actively tlian elsewhere. 



We pass now to the examination of the intimate structure 

 of the septa, and have in this to investigate the distribution 

 of , the muscular fibres. As the framework of each septum we 

 have in Polyparium the supporting lamella, which is clothed 

 with muscles in various stages of development. The surfaces 

 of each septum are unequally furnished with muscles, according 

 as the particular surface is turned towards an intermediate or 

 an interior chamber. The intermediate-chamber-surface is 

 clothed with vertical fibres, the interior-chamber-surface on 

 the contrary with transverse fibres. The vertical muscles 

 are the weakest ; upon a flattened septum they form an unin- 



