11 



at its base, we take the animal out of its cell (fig. 5), the cord always convolves itself in 

 spiral coils. 



Allman has considered this contractile cord as corresponding with the socalled funi- 

 culus in the ordinary Polyzoa ; although it is not as in these, attached to the end of the stomach 

 (the terminal caecum), but on the ventral side of the Polypide's body (Allman has represented 

 it erroneously as attached near the end, on the dorsal side). Moreover Allman indicates that 

 this funiculus is accompanied by a long fascicle of muscular fibres attached to the chitinous 

 cord (axial cord) at the point where the funiculus is joined to the same; and that at the 

 point where the funiculus is joined to the animal's body, this muscular fascicle divides itself in 

 2 bands, of which one goes along the right side, and the other along the left side of the 

 body, finally attaching themselves, each on its own side, to the Pharynx below the Lopho- 

 phorus. These fibres form, according to Allman, the great retractor muscles of the Polypide. 

 This representation, which in fact only depends on spirit specimens, does not, as may be 

 seen, agree with what I have had occasion to observe in our northern species, in which the 

 fascicle of muscles (if one really may venture to use this appellation here) is everywhere, as 

 an integral part, intimately connected with the contractile cord, and is produced only by a 

 peculiar modification of its tissue on the ventral side. Special retractor muscles cannot there- 

 fore, any more than other muscles, be said to be distinguished in the Rhabdopleura. 



The Axial Cord (,.chitinous rod" Allman). 



Through all the creeping stem there extends, as already mentioned, a filiform cord 

 very remarkable by its dark, nearly black color, and, unlike the contractile cord, to which 

 it is about equal in thickness, only slightly flexible, and of a very hard chitine-like consis- 

 tency. This cord (fig. 3. 9. 10. 11 &c. i) which we will call the axial cord, is freely extended 

 in the hollow of the individual chambers into which the stem is divided, and only attached 

 to the septa, which it perforates enlarging itself a little (fig. 11). In conformity with the 

 rarely branched form of the stem, it is only now and then forked; and when this takes place, 

 it is always at one of the septa. Otherwise it forms everywhere a cylindrical tube with very 

 strong, almost horny walls, but always enclosing in its interior (see fig. 12) a soft cellular 

 cord (s) of similar appearance to the contractile cord, and like it colorless and transparent 

 with small dark violet spots of coloring matter, but scarcely "half so thick. This fine cellular 

 marrow which extends through the whole length of the axial cord, seems entitled to be con- 

 sidered as a sort of incompletely defined nervous trunk connecting all the individuals of the 

 colony; as at each partition in the stem, it sends forth a branch which enters into the con- 

 tractile cord of each respective individual animal; and the latter cord does also probably 

 contain in its dorsal part the imperfectly developed elements of nerves. We may therefore 

 herein observe the analogon of the so-called Colonial Nervous system (so strongly developed 

 in the other marine Polyzoa) and specially in the marrow of the axial cord, the common 

 main trunk of the whole colony. 



