2 Trof. lil'Tiitosli's ^^oiesf,'om the 



Amongst others, R. Wagener* (1832) describes tlie 

 alimentary canal in Sabel/a venii/nbrum (S. penici//iis\ L.) as 

 having two sacs in front, such apjiarcntly, from his figure, 

 representing the anterior nephriciia. He ])ointcd out the 

 commissnres connecting the great nerve-cords. 



Milne-Edwards (1838) considered the circulation in the 

 Sabellids to be akin to that of Nephthys and the Nereida^, 

 a dorsal and a ventral trunk being present, and the inner 

 aspect of the integument is supplied with a mnltitudc of 

 vascular filaments for tiie secretory organs, and, with the bases 

 of the feet, ])resent also a capillary >We M'hich probably aids 

 in respiration, though the main iTspiratory organs are the 

 cephalic fans. He did not allude to the special vascular 

 sinus around the gut. 



Grube (1838) gave a general account of the structure of 

 Sabella unispira (Spiroyraphis spallanzani), especially of the 

 alimentary and circulatory systems. He pointed out that 

 Leuckart was wrong in attributing two vascular trunks to 

 each branchial filament. He thought that the anterior 

 (thoracic) nephridia were connected with reproduction. 



Kollikerf, in his researches (1856), deseribes the "carti- 

 lage " of several annelids, such as Sabella unispira (Spiro- 

 graphis spalUuizani), but he was uncertain as to the distinc- 

 tions between the blood-vessels and the nerves of the 

 filaments, and his figures indicate that his " Knorpelfaden " 

 structurally differs from that described here. He noted the 

 specially thickened hypoderm (his epithelial layer). 



De Quatrefages (1850) thought that in the brauchine of 

 the Sabcllidre and Serpulidse are venous and arterial twigs, 

 "which mingle in a system of vessels the "nails of which 

 cannot be distinguished from the surrounding tissues, and iu 

 which respiration is carried on through the thin covering 

 tissues and their cilia. He describes iu these branchiae what 

 he terms a cartilaginous skeleton, composed of cells surrounded 

 by a tough fibrous investment like a periosteum. According 

 to this author, the cephalic ganglia in Sabella jiabellata, 

 Savigny, form two pairs connected by a large commissure, 

 and liom these branches go to the branchise and the eyes. 

 The oesophageal connectives are very short. The visceral 

 system seems to arise from these ganglia as a small twig on 

 each side furnished with two ganglia. The great ventral 

 nerve-cords are separate throughout, though nearer each 

 other posteriorly, and the first ganglia are close to the cephalic, 



• ' Isis,' 1832, p. Goo, Taf. x. 



t ' Untersuchuiigeu z. vergl. Gewebelebre augestelt iu Nizza im 

 Herbste ' (1 Sitzung. 13 Dec). 



