ON CTENODEILUS PAEVULUS. 597 



Claparede,^ who gave the first description of Ct. pardalis, 

 represented the lower lip of this form (pi. xv), as if it were the 

 swollen front portion of the oesophagus, and described it as a 

 '^ tonnenformiger muskuloser Schlund." Professor Ray Lan- 

 kester pointed out some time ago that O. Schmidt's Parthenope 

 serrata was of the same genus as Ct. pardalis, and this too 

 has been figured by Schmidt" with a muscular oesophagus similar 

 to Claparede's. If low powers are used the real nature of the 

 lower lip might easily be mistaken, and I think it quite pro- 

 bable that on re-examination the ''proboscis" of Parthenope 

 serrata would be found to be an organ corresponding to that 

 of the genus Ctenodrilus. 



1 refer to Zeppelin's and Kennel's papers for further details 

 on the subject of the lower lip. Whether the organ is used as 

 a means of taking in food I have not been able to observe, but it 

 probably is. At any rate, it plays an important part in the act 

 of locomotion, as I had the opportunity of mentioning before. 



The Vascular System. — We have a dorsal and a ventral 

 blood-vessel in Ctenodrilus parvulus, just as in the other 

 species, and a communication between the two in front. The 

 dorsal vessel (fig. 1, d.v.) divides into two branches in tiie first 

 segment, which, uniting again below the oesophagus, forms the 

 ventral vessel {v. v.). The vessels are not readily visible in the 

 living animal, except the dorsal, which contains a peculiar 

 organ known as the " rathselhafte " organ (fig. 1, en.), also as 

 '^ corps cardiaque " among French authors. Due to this organ 

 the dorsal vessel is comparatively conspicuous. It is likewise 

 found in the other species of Ctenodrilus, but neither Kennel 

 nor Zeppelin give a satisfactory answer as to its origin or func- 

 tion. I shall say some more about it presently. 



The dorsal vessel takes its origin at the anterior portion of 

 the stomach, where it is attached to the wall of that part of the 



^ Claparede, ' Beobachtungen liber Anatomie und Entwicklungsgeschichte 

 wirbelloser Thiere d. Kiiste von Normandie,' Leipzig, 1863. 



2 O. Schmidt, ' Zur Kenntniss d. Turbellaria rhabdocoela und einiger 

 anderer Wiirmer d. Mittelmeers Sitzungsbericlite d. Kais. Akademie, Wien., 

 vol, xxiii, 1857. 



