■46 GILBERT C. BOURNE. 



' sy. p. Sensory i>apillai. T. Cephalic tentacle, tn. Tentacular nerve. 

 un. Uncini. V. Ventricle of heart, v. aff. Afferent branchial vessel. 

 17. eff. Efferent branchial vessel, v. y. I. Left visceral ganglion, v. g. r. 

 Right visceral ganglion, v. n. Visceral nei-ve. 



[All the figures are of Incisura lytteltonensis.] 



Fig. 1. — A specimen viewed from the left side and below to show the 

 size and shape of the foot, the operculum, the epipodial tentacles, etc. 

 X about 40. 



Fig. 2. — Dorsal view of a female specimen which has been stained and 

 mounted as a transparent object. X 80. 



Fig. 3. — A reconstruction of the alimentai-y tract ; semi-diagrammatic. 

 X 80. 



Fig. 4. — A diagram showing the relations of the right and left kidneys, 

 the heart, pericardium, ovary and oviduct. The extent of the pericardial 

 cavity is indicated by a tiiick black line. X 80. 



Fig. 5. — The nervous system as determined by reconstioictions from 

 sections, x 80. 



Fig. 6. — cj . A transverse section through the postenor part of the 

 head, including both eyes. X 135. 



Fig. 7. — ^ . A transverse section taken just behind the mantle-slit, 

 showing the bi-pectinate character of the right ctenidium. X 135. 



Fig. 8. — (^. A transverse section through the anterior ends of the 

 pedal ganglia. X 135. 



Fig. 9. — ? . A transverse section through the hinder ends of the 

 pedal ganglia. Note the position of the left kidney, h. I., and its open- 

 ing into the mantle-cavity ; the size and extent of the right and left 

 cesophageal pouches, r.ce.p. and Lee. p.; the size and position of the 

 i-ight and left jileural ganglia, pi. r. and pi. I., and the supra-intestinal 

 ganglion, sj). i. ; the pedal ganglia, P., are clearly seen to be composed 

 of a dorsal and a ventral moiety, x 135. 



Fig. 10. — ? . A transverse section passing through the posterior end 

 of the mantle-cavity, showing the large size of the left auricle, au.l.; 

 the orifice of the left kidney, k. r. o. ; the pedal nei'ves, p. ».. which ai-e 

 the posterior continuations of the ventral moieties of the pedal gangha 

 shown in fig. 9. X 135. 



Fig. 11. — $ . A transverse section passing tlu-ough the posterior 

 end of the foot. Note that the large pedal nerves shown in the previous 

 figure do not extend into the hind part of the foot. X 135. 



Fig 12. — $ . A transverse section taken near the terminal pail of 



