76 W. OC. MCINTOSH. 
Fic. 6.—Transverse vertical section, anterior to Fig. 5. The dorsal 
vessel has now split into two trunks, vy. Zeiss, obj. A, oc. 1. 
Fic. 7.—Head of Claparede’s larval “Spio” of 16th July. x 52. 
Fic. 8.—Posterior end of the foregoing form, in a specimen procured in 
October (?). x 52. 
Fic. 9.—Lateral view of the tip of the same example. x 52. 
PLATE 8. 
Fic. 1.—Young form resembling Magelona papillicornis in which the 
head has not yet extended beyond the tentacles, and in which the long larval 
bristles are present anteriorly. «. Constricted region of the alimentary canal. 
gl. Glands of the pharyngeal region. The anterior region of the alimentary 
canal is distended with water. 28th May. x 55. 
Fig. 2.—A similar specimen after the long larval bristles have been shed, 
and viewed from the ventral surface with the tentacles fully extended. x 55. 
Fig. 8.—A more advanced example, in which the basal part of the tentacles 
has larger papillee, and the snout has considerably increased in size; yet the 
long larval bristles are still present. 17th October. x 50. 
Fic. 4.—Dorsal view of the anterior region of Claparéde’s larval ‘*Spio” 
of 16th July. ph. Pharynx. x 52. 
Fig. 5.—Anterior end of the most advanced form of the same species yet 
found. The tentacles are considerably larger. 23rd October. x 52. 
Fic. 6.—Lateral view of an example of the foregoing, showing the chro- 
matophores and feet. 16th July. x 52. 
Fic. 7.—A similar view of a specimen (23rd October), in which peculiar 
refracting bodies, like oil-globules, occurred along the lateral aspects. xX 52. 
