388 REV. E. BOOG WATSON ON THE 



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

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



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

 [Read March 3, 1881.] 



Earn. PiEiraoTOMiitjE,/. Grwyn Jeffreys. 

 Pleurotoma, Lam. 



1. Pleurotoma (Surcula)staminea, 10. Pleurotoma (Sureula) rhysa, 



n. sp. n. sp. 



2. P. {S.) trilix, n. sp. 11. P. (S.) bolbodes, n. sp. 



3. P. (S.) lepta, n. sp. 12. P. (S.) ischna, n. sp. 



4. P. (S.) rotundata, n. sp. 13. P. (Genota) didyma, n. sp. 



5. P. (S.) goniodes, n. sp. 14. P. (G.) engonia, n. sp. 



6. P. (S.) plebeia, n. sp. 15. P. (G.) alractoides, n. sp. 



7. P. (S-j syngenes, n. sp. 16. P. (Drillia) pyrrha, n. sp. 



8. P. (S.) hemimeres, n. sp. 17. P. {D.) pauper a, n. sp. 



9. P. (S.) anteridion, n. sp. 



1. Pleurotoma (Surcula) staminea, n. sp. 



St. 146. Dec. 29, 1873. Lat.,46° 46' S., long. 45° 31' E. 

 Marion Island, Prince Edward Island. 1375 fathoms. Globige- 

 rina-ooze. Bottom temperature 35 0, 6. 



St. 149 j. Jan. 29, 1874. Lat. 46° 43' S., long. 69° 15' E. 

 W. Christmas Harbour, Kerguelen. 105 fms. Mud. 



Shell. — High, narrow, biconically fusiform, scalar, carinated, 

 with spiral threads, thin, white. Sculpture. Longitudinals — the 

 shell is scored with coarse irregular sinuous lines of growth ; but 

 there is no trace of any other longitudinal markings. Spirals — 

 above the middle of each whorl is a strong carination only slightly 

 projecting, but marked by the angulation of the whorl and by the 

 prominence of the thread on its crest. On the bbdy-whorl there 

 is a tendency to a second carination, which runs into the mouth 

 just below the junction of the outer lip, and is thus concealed 

 on all the earlier whorls (it is evident that this inferior an- 

 gulation is a feature which varies much in different individuals). 

 Besides these, the whole surface is covered with irregular and 

 unequal threads ; these are feeblest on the sloping shoulder below 

 the suture : close below the upper keel and on the snout and its 

 conical base they are fine ; about 4 above and 2 below the lower 

 keel are the strongest, but they all tend to subdivide themselves ; 

 and the whole shell is scored by irregular and somewhat broken 

 microscopic lines. Colour translucent white under a thin, pale, 



