MOLLTJSCA OF THE ' CHALLENGER ' EXPEDITION. 217 



Fig. 20. Act. cheltonensis, n. sp. Inferior Oolite, Cheltenham. Eadials and 

 basals only, X4: a, from the side ; b, from beneath. 



21. Pentacrinus asteria. From Barbadoes. Calyx, x4: a, from side; 



b, from beneath. 



22. Solanocrimts Jaegeri, Quenstedt. a, from side ; b, from beneath. 



Copied from Quenstedt. 



23. Pentacrinus Wyville-Thomsoni. North Atlantic. Calyx, X3: a, from 



side ; b, from above ; c, from beneath. 



24. Pentacrinus Jaegeri = Solanocrinus Jaegeri, Goldf. : a, from side ; 



b, from above ; c, from beneath. Copied from Goldfuss. 



Plate XII. 



(Published by permission of the Lords Commissioners of the Treasury.) 



Fig. 25. Ant. macrocnema. Sydney Harbour. Calyx, X 6 : a, from side ; b, 

 from above ; c, radials and basals from beneath. 



26. Act. stelligera, n. sp. Pacific (Stat. 174). Calyx from side, X6. 



27. Act. lineata, n. sp. Bahia. Centrodorsal with two radials, rosette, 



and part of basal star, X : 6a, side view of interior of calyx ; b t the 

 same, seen from above. 



28. Promachocrinus kerguelensis, n. sp. Balfour Bay, Kerguelen. Calyx 



from side, X 6. 



29. Ant. antarctica, n. sp. Heard Island, a, calyx from side; b, radials 



and basals from below : X 6. 



30. Ant. Lundgreni. From the Upper Chalk, Margate. Centrodorsal 



with one basal attached, X 3 : a, from side ; b, from above. 



Mollusca oe H.M.S. 'Challenger' Expedition. — Part VI. 

 By the Eev. Eobert Boog Watson, B.A., F.KS.E., F.L.S., &c. 



[Published by permission of the Lords Commissioners of the Treasury.] 

 [Read April 15, 1880.] 



Turritellid^;, n. sp. 



1. TURRITELLA RUNCINATA. 



2. ACCISA. 



3. CARLOTTiE. 



4. PHILIPPENSIS. 



5. CORDISMEI. 



6. turritella austrina. 



7- deliciosa. 



8. (Torcula) admira- 



BILIS. 



9. (Torcula) lamellosa. 



The genus Turritella is a group well defined, as regards the shel), 

 the animal, and the operculum ; nor is it unmanageably large. 

 There is therefore no prima facie reason for breaking it up as 

 Gray has done; and his destructive process has not justified 

 itself in the characters of the genera he proposed, which are 



