380 WILLIAM A. HASWELL. 



closely comparable with that of the HistriobdelUclee. From 

 the month, situated anteriorly, a long narrow oesophagus 

 runs back ; and contained in a diverticulum of this, given off 

 close to the mouth, is lodged the mastax. 



The various tentacles or papillae tipped with sensory cilia 

 on the anterior region in the Eotifera are closely comparable 

 to the tentacles of the Histriobdellidae. Homologues of the 

 anterior or head legs of the Histriobdellidae are not of 

 general occurrence in the Eotifera. But the groups of 

 unicellular glands forming a viscid secretion, the ducts of 

 which, in Paraseison, open at certain definite spots on the 

 surface of the head, appear to perform a similar function in 

 connection with locomotion to the glands of the anterior legs 

 in the Histriobdellidte, and may be homologous to them. 

 And still closer come the pair of mobile retractile tentacles 

 of Floscularia Hoodii, which would appear to be provided 

 with glands at their bases.^ Homologues of the cirri of 

 Stratiodrilus are readily to be found in the processes or 

 papillae tipped with sensory cilia on the body of various 

 Eotifera. 



The nervous system of the Histriobdellidae differs from 

 that of the Eotifera in the presence of the ventral chain of 

 ganglia, but the discovery by Zelinka (27) of a subcesopha- 

 geal ganglion in Callidina and Di scop us serves to greatly 

 reduce this difference. 



The nephridial system, like the nervous, differs from that 

 of the Eotifera in partaking (though in this case only to a 

 slight extent) in the metamerism of the body, and also in the 

 absence of ciliary flames. 



The reproductive system is readily capable of being con- 

 strued as a direct development from that of the Eotifera. 

 One of the most striking points of resemblance is the median 

 penis with the associated mode of impregnation. The I'ela- 



' I obtain my information on this point from Hudson and Gosse's ' Koti- 

 fera,' in which it is stated (p. 55), "Mr. Hood tells me that both in young 

 and adult specimens he has seen brown granular matter discharged from their 

 free ends." 



