CHARACINIDAE FROM VENEZUELA—SCHULTZ 257 
Mylossoma acanthogaster NorMAN, Proc. Zool. Soc. London, 1928, pt. 4, p. 812 
(Maracaibo Lagoon, Venezuela). 
The following collections were made by Leonard P. Schultz in the 
Maracaibo Basin of Venezuela during 1942: 
U.S.N.M. No. 121347, 12 examples, 154 to 294 mm. in standard length, from 
the Rio Apén about 35 km. south of Rosario, February 26. 
U.S.N.M. No. 121848, 5 specimens, 104 to 216 mm., Rio Palmar at bridge 70 
km. southwest of Maracaibo, March 6. 
The shape of this species changes remarkably with increase in size, 
the body becoming more elongate. The relative positions of the in- 
sertion of pelvics and origin of dorsal fins are variable. These dif- 
ferences are recorded in table 4. The average length of the anal 
base and the average of the greatest depths of the body for the follow- 
ing standard lengths were computed as shown in table 3. 
TABLE 3.—Variation in Mylossoma acanthogaster 
AV AV 
Standard lengths (in mm.) iene netacal Greate dope Eee of 
ned BubGde pecimens 
VOTO Ae Ce IVA gt ANSARI SN RU I es COU et aU eS OL ee 40.4 69. 2 1 
TAS AO a Saag NE AS MS TLE SRS AA oT A ON 38. 1 65.0 1 
TESCO Ze a OLS USER OU AG AUP Ae RI OE CMY SA tO 35. 5 59. 2 3 
FV 1.0 0 ata Pro ALN AT SAL ORRNU eC UN ut dae eee aU 36. 1 54.5 6 
DAO DOH BUT NU on OAS AW ab ira NELURONNCA 7 Uk NINO SFI d 2 a i DR EAL EN Bes BR aR ARIS a ee 34. 7 56. 2 2 
DOs) MSI MARIE BANTER as NOP ASRNCANIANT AUM(UNCA PR RA Acad ye a a dye aay LL 35.2 57.8 2 
PHS OI BSS Ora EAE OMRON MEA ck et De a De ee a TV 32.8 53.1 1 
PaCS DAS NS NG (a AIRC SVEN Se NI GEO LAN SNUG ts PLE NU oe ony ea LU 32.6 §2.4 1 
TaBLE 4.—Measurements, expressed in hundredths of the standard length, made on 
Mylossoma acanthogaster 
Standard length (in mm.) | 104 | 134 | 154 | 163 | 164 | 177 | 178 | 179 | 182 | 195 | 198 | 201 | 216 | 235 | 237 | 256 | 294 
i en | ee a | a ee 
32. 8/32. 6 
53. 1/52. 4 
52. 8/52. aD 0/49. 8/53. 7/52. 3/52. 3/50. 0/50. 3 
58. 2,52. ne 0/58. le ie a ite 8/58. 1 
TaBLE 5.—Counts made on Mylossoma acanthogaster 
35. 8|35. 7/35. 4/36. 3/39. 8/29. 6/34. 935. 5 
Length.of anal base___-_--- 40. 4:38. 1/35. 7/35. 0/35. 9/36. 1/37. 1 
58. si a 2154. iL 2/52. 3)58. 2/57. 4 
Greatest depth___________- 69. 265. — 0,61. 4/57. ni 5/57. 2 
Snout to pelvic insertion___|53. 8/56. 7/54. 5) 57. 6/54. 2 j52. 5/51. 0/54. 2 
Snout to dorsal origin____-_|59. 6/59. 7/56. 5/57. aE alee 2|57. ye 4 
Number of fin rays Number of eu rere on first gill 
Above At 
angle angle 
re rr cr | eS | ee ee a a RT | a Se | mmD eS 
Dorsal Anal Pectoral Below angle 
HipytA sd 15 Maceo era eee lt coe | Uo LAN fy 15 hey AG|NG, D7 Nd, ASIN 15) || 136) |i den| 208) 21122 
