1(11) THE VOYAGE OF H.M.S. CHALLENGER. 



Observations. — It is extremely difficult to decide whether one is right in considering 

 the specimen taken a1 Station 195 as specifically distinct from Scalpellum regium. 

 After long hesitation, I have decided to do so, in the first place, because the capitulum as 

 a whole has a more elongate shape; in the second place, because the chitinous membrane 

 which rovers the valves of Scalpellum moluccanum is smooth or almost smooth, whereas 

 in most specimens of Scalpellum regium it is distinctly hairy. In the third place, the form 

 df i he upper latus is different, being a great deal broader in Scalpellum regium than in 

 the present specimen. As in other similar cases, these differences may turn out — by 

 intern i ediate forms being discovered — not to be of enough importance for creating 

 different species. In that case our Scalpellum moluccanum will retain the. significance 

 of a so-called local variety. 



Scalpellum regium (Wyv. Thorns.), n. sp. (PL IV. figs. 3-5 ; PI. IX. fig. 12 ; 

 PL X. figs. 1, 2). 



Surface of the capitulum covered by membrane, which in some specimens is rather 

 smooth, in others hairy. Valves fourteen. Carina simply bowed, with the roof laterally 

 convex. Umbo of the carina at the apex. Upper latus quadrangular. Peduncle short. 

 Complemental males numerous. 



This is one of the largest species known. It is represented by numerous specimens, 

 and was found at two different stations, which, however, are close to one another and 

 have almost the same depth. This depth almost reaches 3000 fathoms. The different 

 bottles containing this species are labelled Scalpellum regium, n. sp., or Scalpellum 

 regium, Wyv. Thomson. Though no sufficient description of this species has been 

 published, I retain the name given to it by the chief of the scientific staff on board the 

 Challenger, the late Prof. Sir C. Wyville Thomson. 1 This name has been mentioned 

 in another printed publication, viz., in a paper of M. Al. Humbert, inserted in the 

 Journal de Zoologie, iii., 1874, p. 133. No doubt M. Humbert found the name in one 

 of the letters sent by Dr. v. Willemoes Subm to Prof. v. Siebold, and published in the 

 Zeitschr. f. Wissensch. Zoologie, or else in the Reports from the Challenger. 2 



Capitulum with fourteen valves, which are covered by membrane, which in some 

 of the specimens is almost entirely smooth, in others, however (and especially 

 in the older specimens), it is rather hairy. The capitulum is very robust, almost quad- 

 rangular ; very thick near the peduncle, and flatter towards the apex. The valves have 

 their umbones at the apex, and show very distinct lines of growth. Tergum, scutum, 

 and upper latus are very large ; the valves of the lower whorl comparatively small. 



Scutum trapeziform, only one and a third as long as broad. Convex, with the 



1 Nature, 1873, vol. viii. p. 347. Thomson, C. Wyv., Voyage of the Challenger, Atlantic, vol. ii. p. 4. 



2 Proc. Roy. Soc, vol. xxiv., No. 170, p. 574. 



