90 GRIFFIN. 



•p. c, pedal commissure. 



par. gn, parietal ganglion. The right pleural ganglion lies 



between the pedal and parietal ganglia, closely joined to the 



latter. 

 V. gn, visceral ganglion. 

 p. p. c, para-pedal commissure. 

 pi. gn. L, left pleural ganglion. 

 p. gn. L, left pedal ganglion. 

 cr. pi. c, left cerebro-pleural connective. 

 cr. p. c, left cerebro-pedal connective. 

 6. gn, buccal ganglia. 



34. Ventral view of pedal, pleural, parietal, and visceral ganglia. 



35. Central nervous system of a specimen of Aclesia freeri sp. nov. in 



which the viscero-parietal ganglion is some distance back of the 



oesophageal nerve ring, approaching the condition found in 



Tethys (Aplysia). 



c, cerebral ganglion. 



p, left pedal ganglion. 



p', right pedal ganglion. 



pi, left pleural ganglion. 



pV, right pleural ganglion. 



p. par, pleuro-parietal connective. 



pi. V, pleuro-visceral connective. 



V. par, viscero-parietal ganglion. 



36. Right lateral view of cerebral, pedal, pleural, and parietal ganglia. 



(Drawn by Griffin.) 



TEXT FIGURES. 



Fig. 1. Diagram of the pallial complex of Aclesia freeri sp. nov. A, anal 

 papilla; bv, afferent branchial vein; mr, mantle ridge, i. e., the 

 projecting free margin of the reduced mantle; n, nephridium; o, 

 osphradium; par, parapodium; p. e., pericardium; v, vein of left 

 side of body running beneath the pericardium and nephridium; 

 vii, vulva; x, aperture by which the blood from the hamocoel and 

 veins of the right side of the body enters the branchial vein. 



2. Outline of a mandibular plate of Aclesia freeri sp. nov. The figure 



within the outline represents four of the rods of which the plate 

 is composed. The concave border of the plate is anterior. Actual 

 dimensions, 5 millimeters high, 3 millimeters wide at bottom, 1 

 millimeters wide at top. 



3. Central tooth, first and second inner laterals, and four outer lateral 



teeth of the radula of Aclesia freeri sp. nov. 



4. Cuticular spines or thorns upon the inner surface of the pharynx of 



Aclesia freeri n. sp. The four spines at the left are from the 

 anterior, the ones to the right from the posterior region of the 

 part of the pharynx thus armed. 



5. Diagram of the reproductive system of Aclesia freeri sp. nov. 1, 



vulva; 2, copulatory recess; 3, spermatocyst ; 4, mucous gland 

 (nidamental gland) ; 5, proximal portion of oviduct; 6, album- 

 inogenous portion of oviduct (albumen gland) ; 7, hermaphrodite 

 gland; 8, hermaphrodite duct; 9, ovarian portion of sperm-oviduct; 

 10, spermatic portion of sperm-oviduct; 11, spermatheca. 



