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Observation. In the smaller specimens the breadth of the capitulum at the base is 

 about the same as at the height of the upper latus. In these the carinal margin of the tergum 

 is not so distinctly divided into two parts, the apex of the carina does not project freely and 

 the umbo of the carinal latus is not seated at the tip of a triangle which projects beyond the 

 line of the carina. As I feel convinced that these smaller specimens, some of which were 

 attached to the larger, belong to this species, I am inclined to admit that several of these 

 differences result from there being a considerable difference with regard to age and maturity 

 between the specimens at my disposal. 



(Remark when correcting the proof of the description given above.) 

 This species is, without doubt, nearly related to Sc. sociabile Annandale^ from Bali Straits, depth 

 1 60 fathoms = 310 m. The characteristic figure Annandale gives of the group of specimens 

 of his new species is perhaps not cjuite so useful for recognizing an individual specimen. As 

 there also occur differences between his description of the valves, of the appendages, mouth- 

 parts etc. and mine, I think it better therefore to keep my species separate; future investigators 

 will, no doubt, easily find out whether the two species are identical or not. 



20. Scalpelluin iiiibricatuiii n. sp. PI. VIII, fig. 15 and 15^. 



Valves 14. Surface of valves covered by a slightly villous chitinous membrane. Carina 

 very large, nearly reaching to the apex of the tergum, simply bowed, roof furrowed longitudinally. 

 Rostrum narrow, indistinct. Infra-median latus narrow, with the umbo at the apex. Carinal latus 

 with the umbo at a short distance from the base, slightly projecting beyond the line of the carina. 



This species is represented by one specimen only. 



The capitulum is rather narrow, the carinal margin regularly bowed, the curvature 

 nearly reaching to the apex of the scutum. The surface is covered by a thin slightly villous 

 membrane which makes it difficult at first sight to distinguish the margins of the valves. There 

 are slight interspaces between the different valves, specially distinct in the corner where the 

 upper latus, the carinal and infra-median latera meet. 



The scutum is quadrilateral; the length not quite twice the breadth. The apex is 

 pointed and slightly overlaps the tergum. 



The tergum is triangular, its occludent margin nearly quite straight. The apex is 

 bluntly pointed and hardly produced. 



The carina is very large, nearly reaching to the tip of the tergum. It has a very 

 pronounced curvature. It has well developed sides and a roof that increases in breadth though 

 not very much from the apex downwards. The roof is distinctly furrowed longitudinally. 



The upper latus is pentagonal ; its umbo is at the apex which fits into the angle 

 formed by the scutal margin of the tergum and the lateral margin of the scutum. 



The rostrum (PI. VIII, fig. 15^) is narrow, slightly increasing in breadth downwards, fitting 

 exactly between the rostral margins of the rostral latera, more or less concealed by membrane. 



' .A.NNAN'l)Ai.E, N., Malaysian Bainacles in tlie Indian Museum. Memoirs of the Asiatic Society of Bengal. 1, 5, 1905, p. 77, 

 pi. VIII, fig. 2. 



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