06 PROCEEDINGS OF THE ACADEMY OF [Vol. LXX1V 



Fig. 5 — Lucidella (Poenia) lirala. Centrals (x6). Compare 4 for marginals. 



Fig. 6— Helicina neritella. Centrals (in row instead of in the more common 

 position); tip and inner view of 4th marginal; a, b, c: tips of 

 marginals further out (exact position unknown); d: edge view 

 of distal end of a marginal to show sickle-shaped tip. (x3). 



Fig. 7 — Helicina (Tenuis) tenuis. Centrals and tips of 1st, 5th, and 12th 

 marginals (x3). 



Fig. 8 — Helicina (Oxyrhombus) amoena. Centrals and tips of 1st, 3rd and 

 9th marginals (x3). 



Fig. 9 — Helicina (Tristramia) zephyrina. Centrals and tips of 1st, 3rd, 

 6th and 12th marginals; outer view of 2nd; inner view of 7th; 

 edge view of distal end of 17th ;and edge view of proximal 

 end of 8th to show U-shape of base. (x3) 



Plate IV. — Hcndersonia, Oligyra, Helicina and Schasicheila. Capituliform 

 Complexes. 



Fig. 10 — Hcndersonia occulta. Comb-lateral and accessory plate separated 

 (x3). 



Fig. 11 — Oligyra orbiculata. Comb-lateral and accessory plate separated. (x3). 



Fig. 12 — Oligyra (Succincta) flavida strebeli. Comb-lateral and accessory 

 plate united (x3). 



Fig. 13 — Helicina (Tristramia) zephyrina. Comb-lateral and inner end of 

 accessory plate united (x3). 



Fig. 14 — Helicina (Tenuis) tenuis. Comb-lateral and accessory plate separa- 

 ted (x3). 



Fig. 15 — Helicina (Oxyrhombus) amoena. Comb-lateral and accessory plate 

 separated (x3). 



Fig. 16 — Schasicheila (Emoda) silacea. Comb-lateral and accessory plate 

 separated (x3). 



Fig. 17 — Helicina neritella. Comb-lateral and accessory plate separated. (x3) 

 a. cusp-bearing portion of comb-lateral, b. handle or base of 

 comb-lateral, c. triangular outer projection of comb-lateral; 

 this forms a support for: d. continuation of cusp-bearing 

 portion, e. depression and thinning of comb-lateral (shown by 

 dotted lines) ; on opposite side from that viewed. This is for the 

 reception of the base of the comb-lateral next anteriad (above 

 in figures), f. Portion of accessory plate which fits under the 

 triangular projection of the comb-lateral (c). g. lanceolate 

 appendix of the accessory plate, h. reflected portion, which 

 invests the outer end of(d). x. termination of each piece 

 (when united in natural position) marked on the other. 



17A — Helicina adspersa. Comb-lateral and accessory plate, slightly separat- 

 ed (x3). 



Plate V. — Schasicheila, Lucidella, Aphanoconia, and Oligyra. Radulae. 



Fig. 18 — Schasicheila hidalgoana. Centrals and tips of 1st, 4th, 12th and 



21rst marginals. (x5). 

 Fig. 19 — Schasicheila (Emoda) silacea. Centrals and tips of 1st, 4th, and 



12th marginals (x3). 

 Fig. 20 -Schasicheila hidalgoana. Capituliform complex united (x3). 

 Fig. 21 — Lucidella (Poenia) lirala. Capituliform complex united (xO). 

 Fig. 22 — Lucidella aureola. Capituliform complex united (x6). 

 Fig. 23 — Aphanoconia (Sphaerocouia)v erecunda. Central sand tip of 1st 



marginal (x5). Comb-lateral and accessory plate separated 

 (x3). 

 lig. 24 — Oligyra (Succinta) oweniana coccinostoma. Centrals and tips 



of 1st, 3rd, 7th, and 12th marginals, and edge view of distal 



end of 4th to show wings (x5). Comb-lateral and accessory 



plate separated (x3). 



