OBSERVATIONS ON FISH SCALES. 
137 
Scales elongate (8 mm. long, slightly over 3 yj broad), parallel sided, nucleus 2 mm. from anterior 
end; posterior end broadly and shallowly emarginate; circuli fine and dense; a single delicate 
radial line runs down the middle of the scale from the nucleus to the posterior margin, but 
otherwise there are no basal radii; apical field rugose, with very weak radii (Sittang River, 
E. W. Oates). O. microlepis 
Scales circular or nearly; nucleus nearly central; no basal radii, but the basal region more or less 
undulate... 1 
1. Scales broader than long; only feeble rudiments of basal radii; about 13 wavy apical radii (Sittang 
River, E. W. Oates).. O.alfrediana 
Scales larger (diameter 4^2 mm.); apical radii few, strong but very irregular and broken, wavy; a 
very deep-bodied fish (Sittang River, E. W. Oates). O.feae Vinciguerra 
Scales smaller (diameter about 3 mm.), apical field without circuli, but with weak and broken 
wavy radii (Sittang River, E. W. Oates). O. cotio (Hamilton Buchanan) 
The last three seem closely allied, but O. microlepis is very different and is probably not truly con¬ 
generic. In Gunther’s Catalogue Osteobrama stands next to Chanodichthys. The scale of Chanodich- 
thys, without basal radii, is in fact of a similar type, but much larger, with the numerous apical radii 
not distinctly wavy. 
Osteochilus Gunther. Zool. Anzeiger, xxxvi, p. 253, fig. 4 ( 0 . kahajanensis ). I have seven species 
from the British Museum, which are separable thus: 
Apical interradial area striate with longitudinal converging circuli. 1 
Apical interradial area evidently tuberculate, the circuli broken up. 2 
1. Scales about 7 mm. long and broad (Menam River, Siam; Royal Siamese Museum). . 0 . schlegelii 
Scales about 4 mm. long and 3-3X broad (Menam River, Siam; Royal Siamese Museum). 
O. melanopleurus 
2. Scales very large, 14 mm. long and 13 broad; apical radii wavy, basal radii very few and irregular 
(Baram River, Sarawak; C. Hose). O. hasseltii (Cuvier & Valenciennes) 
Scales smaller; apical radii essentially straight. 3 
3. Lateral radii few, reaching nuclear area; scales about 7 mm. long and 6 broad (Sittang River; 
E. W. Oates). O. neilli (Day) 
Lateral radii numerous, all or most failing to reach nuclear area.4 
4. Basal margin strongly trilobed (Deli, Sumatra; Moesch). O. waandersii 
Basal margin weakly undulate. 5 
5. Scale about 10 mm. long and 9 broad; skin pale with dark dots. (Baram district; C. Hose). 
O. kahajanensis 
Scale about 7 mm. long and 6 broad; skin brown (Tinjar River, 200 miles from sea; C. Hose). 
O. mttatus 
All are broadly rounded apically, essentially truncate basally, with evident laterobasal cor¬ 
ners; nucleus far toward the base (least so in O. neilli ); apical radii well developed, basal very 
poorly, feeble and irregular. The genus is a compact one on the scales, and the specific distinc¬ 
tions given are probably not all valid. (See also remarks under Cirrhina.) 
Paracheilognathus Bleeker. Proc. Biol. Soc. Wash., xxn, p. 157; Zool. Anzeiger, xxxvi, p. 477. Scales 
of P. rhombeus are about 2^ mm. long, 4^ broad; circuli not at all dense. 
Parapelecus Gunther. P. argenteus from Kiu-Kiang (Styan; B. M.) is a remarkable fish, with the scales 
inserted obliquely, and the lateral line abruptly bent. The scales are about 4 mm. long and 6K 
broad, covered with thin skin to the base. There are fine basal circuli, but no basal radii; in the 
apical field the circuli are wanting, but there are numerous irregular delicate radii. Thus the 
scale combines the shape of the Rhodeines with the sculpture of the Gobio group. Except for the 
larger size and covering of pinkish skin, the scales are extremely like the broader ones of Leucogobio 
mayedce. 
Phoxinellus Heckel. Proc. Biol. Soc. Wash., xxn, p. 216. The locality given as Oued el Mahd should 
be Oued (or Wed) el Mahdi; the printer took the i for a semicolon. The two lots of scales repre¬ 
sented Phoxinellus chaignoni (Vaillant) and P. callensis (Guichendt), which Boulenger now regards 
as distinct, though very closely allied. I fail to find any difference in the scales of the two. 
Phoxinus Rafinesque. Proc. Biol. Soc. Wash., xxn, p. 186 and p. 216; Zool. Anzeiger, xxxvi, p. 476. 
Pseudogobio Bleeker. Zool. Anzeiger, xxxvi, p. 478, fig- 1 ( P • esocinus Schlegel). 
Rasbora Bleeker. Proc. Biol. Soc. Wash., xxm, p. 144. 
