54 PTEROPODA. [Thecosomata. 



KEY TO SPECIES. 



A. Dorsal lip thickened into a pad. 



a. Shell with lateral points . . . . . . . . trispinosa. 



B. Dorsal lip with a thin margin. 



a. Posterior portion of the ventral lip markedly projecting 



laterally . . . . . . . . . . . . longirostris. 



>in. Ventral lip not more developed than the dorsal. 



b. Shell without appreciable lateral points . . . . telemus. 



bb. Shell with distinct lateral points. 



c. Upper lip flattened posteriorly . . . . . . uncinata. 



cc. Upper lip directed straight forwards . . . . inflexa. 



1. Cavolina inflexa, Lesueur, 1813. Plate 6, fig. 2. 



Hyalcea inftexa, Lesueur, Nouv. Bull. Soc. Philom., iii, 1813, 285. pi. 5, 

 f. 3. H. dongata, Lesueur, MS., in Blainville, Diet. Sci. Nat., xxii, 1821, 

 82. H. vaginellina, Cantraine, Bull. Acad. d. Sci. Bruxelles, ii, 1835, 

 380. H. labiata, d'Orbigny, Voy. Amerique merid.. v, 1836, 104, pi. 6, 

 f. 21-25. H. uncinata, Hoeninghaxis, MS., in Philippi. Enum. Moll. 

 Sicilise. 1836, 101. pi. 6. f. 18. not of Rang. Diacria inflexa, Lesueur : 

 Gray, Cat. Moll. Brit. Mus., pt. ii, Pteropoda, 9. Hyalcea imitans, 

 Pfeffer, Abhandl. Naturw. Ver. Hamburg, vii, 1880, 90, pi. 7, f. 9a. 

 Cavolinia inftexa, Les. : Pelseneer, Chall. Rep., xxiii. 1888, 85 ; Hedley, 

 T.X.Z.I., xxxviii, 1905 (1906), 76. 



Shell elongated, conical, compressed on each side, elongated pos- 

 teriorly, terminated by a recurved point, laterally armed with a short 

 point ; aperture ovately transverse, laterally deeply cleft. (Gray.) 



Hob. Off Great Barrier Island, in 110 fathoms. 



2. Cavolina longirostris, Lesueur, 1821. Plate 6, fig. 9. 



Hyahvo, longirostris, Lesueur, MS., in Blainville, Diet. Sci. Nat., xxii, 1821, 

 81 ; Pelseneer, Chall. Rep., xxiii, 1888, 79. 



Shell ovate-globular, terminated anteriorly with a rather long, 

 arched, channelled beak, posteriorly shortly truncate, laterally pro- 

 vided with short hooked wings, inferiorly 3-ribbed ; aperture trans- 

 verse, narrow. (Gray.) 



Var. strangulata, Hedley, 1907. Plate 6, fig. 8. 



Cavolina longirostris, var. strangulata, Hedley, Rec. A.M., vi, pt. iv, 1907, 

 299, pi. 54, f. 13. Cavolinia, sp., Hedley, T.N.Z.I., xxxviii. 76. 



This differs from the typical form by the sudden lateral contraction 

 of the rostrum, which distally expands in a spout. In the typical 

 form the rostrum is produced more gradually from the anterior dorsal 

 margin than in the variety. In var. strangulata the posterior lateral 

 angles are less developed. 



Hob. Off Great Barrier Island, in 1 10 fathoms. 



