HEKATEEOBRANOHUS SHEUBSOLII. 199 



EXPLANATION OF PLATES XXI and XXII, 



Illustrating Miss Florence Buclianan's paper on '^ Hekatero- 

 branehus Shrubsolii, a new genus and species of the 

 family Spionidse/^ 



Fig. 1, — Lateral surface view of the whole animal, p-o. Prostoniium. m. 

 Mouth, t. Cephalic tentacles, with cilia and tactile hairs, br. Branchise. 

 V. c. Ventral collar of 1st segment. d. c. Dorsal collar formed by the two 

 " cirri " of the 2nd segment, a. Anus. The ventral crotchet chsetas are 

 seen beginning in the Sth segment. 



Fig. 1a. — The same, natural size. 



Fig. 2. — Semi-diagrammatic view of the left side of the animal from the 

 inside, as would be seen were the animal cut in two by a longitudinal, vertical, 

 nearly median section. The tentacle (^.) and branchise [br.) are supposed to 

 have been cut separately. The digestive, vascular, nervous, and excretory 

 systems are shown, m. Mouth, ph. Pharynx, ces. (Esophagus, int. In- 

 testine (large, intersegmeutally constricted part), int' . Intestine (narrow, 

 non-constricted part). a. Anus. d. v. Dorsal vessel, t. v. Vessel of 

 tentacle (its junction with the branchial vessel, which meets the ventral vessel, 

 is seen in Fig. 12). d. br. v. Branchial vessel in connection with the dorsal 

 vessel. V. br. v. Branchial vessel in connection with ventral vessel, v. v. 

 Ventral vessel. si7i. Sinus, d. s. v. Dorsal vessel nipped off from the rest of 

 the sinus, but lying close to the wall of the intestine, containing the intra- 

 vascular ridge, n. c. Nerve-cord. gng. Prostomial ganglion, neph. e. Ex- 

 ternal limb of thoracic nephridium, opening to the exterior in the 2ud 

 segment, neph. i. Internal limb of thoracic nephridium. ccel. Ccelom. sepi. 

 Septa. Longitudinal muscles would really be seen in such a view underlying 

 the epidermis, but are omitted for the sake of clearness. 



Fig. 3. — Ventral view of anterior extremity. A. Showing ventral collar 

 (y. coll.), and prostomium lying beneath it. The collar is pushed forwards, 

 and so covers the mouth. B. The pharynx {ph.) everted, hiding the pro- 

 stomium. 



Fig. 4. — Chsetae. A. Notopodial capillary chaeta. B. Neuropodial capillary 

 chseta. C. Neuropodial crotchet (side view). C. The same (ventral view). 



Fig. 5. — Transverse section through the thoracic region of a specimen 

 in which no gonads were developed (stained with hsematoxyliu). Epid. 

 Epidermis, cm. Circular muscle layer of body-wall. c.m^. Circular muscle 

 layer of dorsal vessel {d. v.). c. nP. Circular muscle layer of alimentary 

 canal, d. I. m. Dorsal longitudinal muscles of body-wall. v. L m. Ventral 

 longitudinal muscles of body-wall. c. ep. Ccelomic epithelium, coel. Ccelom. 

 int. ep. Intestinal epithelium, ntp. Notopodial chsetse. nrp. Neuropodial 



