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ï. Tympanomerus ceratophorus (Koelbel). PI. 2, Fig. 2. 



1898. Dioxippe ceratophora Koelbel. Wiss. Erg. Reise Béla Széchenyi in Ost-Asien, Bd 2, 

 p. 573, PI. 1, f. 8—12. 



Stat. 33. River near Pidjot, Lombok. 1 cf. 



Though Koelbel has given a most accurate description and an excellent figure of this 

 species, the paper cited above appears to be very rare ') and I presume, that it is therefore 

 not superfluous to give a new description. 



As in Tympanomerus pusillus the carapace is rather flattened, roughly pentagonal, and 

 with the regions very obscurely defined. The gastric area is broad, smooth, with a short 

 longitudinal sulcus on the anterior part, which sulcus is sharply defined posteriorly, but gradually 

 disappears proximally. Hepatical regions scarcely distinct from gastric area, sloping laterally 

 and forward, towards the orbit. Cervical groove, dividing gastric and cardiac area, rather distinct, 

 short and concave. Cardiac area small, hexagonal ~). Intestinal region occupying the entire 

 posterior part of the carapace, and defined anteriorly, as is usual in this genus, by a ridge, 

 which in our species is curved, with the concavity turned backward; the region presents so a 

 narrow, crescent-shaped outline. Branchial regions somevvhat roughened and sloping like the 

 hepatical regions, but not at all separated from the latter; only the inner branchial areas are 

 somewhat defined and faintly bulging. 



Front, as Koelbel remarks, at base about x / 6 the distance betwèen the external orbital 

 angles, with slightly converging side borders that pass with very much rounded angles into to 

 somewhat convex anterior border, which latter is almost imperceptibly produced in the middle ; 

 the front is almost perpendicularly deflexed and exhibits two stiff hairs implanted near the 

 anterior angles and also shown in the figure 2. Supra-orbital borders wavy, much sloping back- 

 ward, especially in their outer half, but almost transverse near the outer angle, microscopically 

 beaded. The distance between these angles is about 1 l L times the length of the carapace ; the 

 angle themself (fig. 2a) is peculiar, it is short, directed straight outward and very obtuse 3 ), 

 below the lateral margin there are some few feathered hairs projecting beyond the margin ; 

 posteriorly the angle is foliowed by a deep, almost semi-circular notch, ending posteriorly in a 

 very small tubercle (epibranchial angle); the distance between these angles is very slightly less 

 than that between the anterior angles of the carapace 4 ). Behind the epibranchial angle the 

 lateral margin of the carapace describes a sigmoid curve, which is iinely granulate, with a row 

 of curious, club-shaped, short hairs (auditory or sensory) in its anterior part, and sloping almost 

 perpendicularly towards the base of the penultimate leg. Dorsally this lateral margin is accom- 

 panied by a less curved and not continuous ridge at either side of the carapace, thus separating 

 off a strip of the carapace, that is roughly granulate; in dorsal view we remark the bulging sub- 

 branchial region projecting beyond the sigmoid lateral margin, the distance between the posterior 



1) Thanks to ihe kindness of Dr. DE Man I have been enabled to consult it. 



2) Koeluel nientions a very faint longitudinal groove on this region, which I have not been able to detect. 



3) According to Koelbel's figure the lateral margin is senulate; in my specimen I observed likewise three small prominences, 

 that were, hovvever, much less conspicuous. 



4) Koei.bel's measurements indicate, that in his specimen the reverse is the case. 



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