330 FRANK E. BEDDARD. 
to make a definite assertion upon the matter. But in one speci- 
men the cavity of the branchia contained a quantity of oval or 
fusiform bodies (fig. 11), of problematical nature. These moved 
to and fro with the contractions of the branchiz, but I found 
none in the body, nor did I ever see them pass the diaphragm. 
In the above account of the branchial organs I have com- 
pared them with those of Chetobranchus. The important 
differences lie in the position, the contractility, and the inde- 
pendence from the setz of the branchiz in Branchiura. The 
fact that in Chetobranchus the sete are embedded in the 
branchiz suggests a comparison with the parapodia of Polychete 
Annelids; but it must be remembered that the enclosure of 
the sete within the branchial processes of Chetobranchus 
appears to be secondary. They are at first, partially at least, 
unenclosed by the branchie. In Branchiura the branchie 
recall the simpler forms of gills in certain Cheetopods, perhaps 
also the cirri. I am not, however, disposed to lay any stress 
upon these resemblances, apart altogether from the wide separa- 
tion between the existing Polycheta and Oligocheta; it is 
quite intelligible that structures of this kind may have arisen 
independently. Indeed, I am of opinion that there is no 
genetic connection between the branchie of even the four 
Oligochetous genera now known to possess these organs, viz. 
Dero, Alma, Chetobranchus, and Branchiura. Though 
Dero and Chetobranchus are probably both Naids, their 
branchiz are too different in structure and position to admit 
of a direct homologisation without further facts than those 
known. Branchiura I believe to be a Tubificid, and its 
branchie are again different. Alma cannot at present be 
certainly regarded as an Oligochete at all;! if it is, I am 
inclined to regard its branchiz as more like those of Bran- 
chiura than those of either Dero or Chetobranchus. 
1 Its resemblances to such a Capitellid as Mastobranchus have been 
pointed out; but Hisig (‘Monograph der Capitelliden’), though admitting 
these resemblances, leans to the opinion that it is an Oligochete, on account 
of the blood-vessels described by Grube. There are, of course, no blood- 
vessels in the Capitellide. 
