344 OBSERVATIONS ON THE CHLORAEMIDAE, 



to regular peristaltic contractions, driving the blood from behind 

 forwards. This vessel contains the unpaired cardiac gland, to 

 which reference is made below. In the peristomial region it 

 divides into two main afferent branchial vessels, each of which 

 divides to give rise to the corresponding tentacular and branchial 

 branches. 



In Coppingeria the arrangement of the vessels conforms in all 

 essential respects to that described by Claparede for Stylarioides 

 (Trophonia) monilifer. There is a peri-intestinal sinus or rather 

 plexus of sinuses in the wall of the stomach. From this, at the 

 anterior end of the stomach, passes forwards the short dorsal 

 vessel or heart, almost parallel with and on the dorsal side of the 

 oesophagus. This bifurcates in the anterior part of the peris- 

 tomium. Each branch enters the branchial stalk and breaks up 

 anteriorly into a number of afferent branchial vessels (fig. 25, br.), 

 each running to the end of one of the branchiae. The blood 

 returning from the extremities of the branchiae by means of the 

 efferent branchial vessels must be carried back by a trunk, which 

 appears in my sections as a vessel of small size, running backwards 

 just above the oesophagus. This bifurcates behind, the two 

 branches thus formed embracing the oesophagus at its posterior 

 end and uniting below with the ventral vessel. The latter runs 

 forwards only a short distance in front of this junction, but is 

 continued backwards throughout the body. On the dorsal side 

 there is given off from the heart a dorsal vessel which runs back- 

 wards throughout the length of the body on the dorsal aspect 

 above the alimentary canal. 



Claparede (I.e., p. 360) describes the branchial vessels in Styla- 

 rioides monilifer as having lateral diverticula ("anses"), and in his 

 figure of a portion of a branchia (plate xxv., 1b.) transverse dotted 

 bands are described as the diverticula in question, covered with 

 brown pigment. There are no lateral diverticula in Coppingeria nor 

 in Stylarioides cinctus. The branchial vessels in the former are 

 accompanied by bands of a granular material which colours 

 deeply with haematoxylin and which may contain pigment; in 

 the latter there is a reddish-brown pigment. These pigmented 



