2G2 Prof. M'lutosh's Notes from the 



his "Ammocliariformia," keeping under his " Syllidiformia 

 Spionina" the Spionidse, CliEetopteridae, Cirratulidae, Ari- 

 ciidae, Chloroeinidae (?), and Opheliidse, an assemblage even 

 more complex than that of Prof. Benham. 



Explanation of the letters used in the figures. 



bv. Blood-vessels. 

 c. Central nervous system. 



cm. Circular muscular coat. 



coe. Coelom. 

 eoel.c. Coelomic corpuscles. 

 dm. Dorsal longitudinal muscles. 



dv. Dorsal blood-vessel. 



ec. Special layer of gut and diaphragm. 

 g. Gonads. 



hp. Hypoderin. 



hpe. Thickened layer of hypoderm. 

 int. Intestine. 



Ip. Lip-organ. 



m. Mouth. 

 mg. Mucous glands. 

 mp. Pore of mucous gland. 



nc. Nerve-cord. 



oes. CEsophagus. 



ov. Ova. 

 spt. Septum. 



st. Stomach. 

 val.p. Valvular process of alimentary canal. 

 vm. Ventral longitudinal muscles. 



vs. Vascular sinus. 



vv. Blood-vessels. 



EXPLANATION OF THE PLATES *. 



Plate VII. 



Fig. 1. Transverse section of the anterior end oi Owenia fusiformis, Delia 

 Chiaje, to show the central nervous system (c). in., mouth, 

 the lining of hypoderm also having a pale band beneath it at 

 mo. The ventral gap in the body-wall is still open, x Zeiss 

 uc. 2, obj. A. 



Fig. 2. More highly magnified view of the central nervous system, c, as 

 part of the hypoderm, hp., cm. Circular muscular coat. 

 X oc. 4, obj. D. 



Fig. 3. Transverse section after the completion of the body-wall in front 

 and the appearance of the lip-organ Ip. nc, nerve-cord. 

 X oc. 2, obj. A. 



Fig. 4. Section behind the foregoing. The vestibule is now contracting, 

 and the lip-orgau, Ip., is in full development, with its inner 

 bitid region and more massive external part. x oc. 2, 

 obj. A. 



* I am indebted to the Carnegie Trust for part of these figures. 



