major chela is always as long or longer than 

 the palm; the fingers are pubescent. The ex- 

 ternal eggs of the female, in early stages of 

 development, are green but turn to dark brown 

 in the advanced, eyed stage. 



Species and Size Composition of 



Culls from the Commercial Catch 



I examined 221 shrimp 42 to 77 mm. long 

 (discarded as too small to sell) on August 4, 

 1952, for species and size composition (table 

 7) . The bulk of the sample was M. macro- 

 brachion (88 percent) while the commercial 

 shrimp M. vollenhovenii made up the remain- 

 ing portion (12 percent). Less than 5 percent 

 of the specimens of M. vollenhovenii were under 

 65 mm. long, whereas only 7 percent of the 

 specimens of M. macrobrachion were larger 

 than 65 mm. M. macrobrachion ovigerous fe- 

 males were numerous and constituted 33 per- 

 cent of the sample, which was a much higher 

 percentage than that of M. vollenhovenii at 

 0.5 percent. The ovigerous females of M. 

 macrobrachion. were 46 to 61 mm. long, and 

 59 percent of them were in the 50- to 54-mm. 

 size interval. The nonovigerous females were 



42 to 72 mm. long; 29 percent were in the 

 55- to 59-mm. size interval. The size range of 

 M. macrobrachion in the sample was similar 

 to that listed by Holthuis (1951) for specimens 

 from Nigeria. 



Throughout the investigation, M. macro- 

 brachion was predominant among culls from 

 the commercial fishery. The commercial fish- 

 ery harvested the adults of both species, with 

 no apparent detriment to either species. 



ACKNOWLEDGMENTS 



My Liberian fishery aide, Momolu P. Mas- 

 saquoi, gave me great assistance on this project. 

 Ivan Pratt of the Oregon State University 

 Zoology Department let me analyze the data 

 and prepare this manuscript for a research 

 course under his supervision. Cmdr. George 

 E. Morris, U.S. Coast and Geodetic Survey, 

 F.O.A., kindly supplied the salinity data for 

 the Monrovia Freeport. Other persons who 

 aided in the investigation were: President 

 William Tubman, Secretary of Agriculture 

 John Cooper, and A. Kini Freeman of Liberia; 

 Fenner Chace and Horton H. Hobbs, Jr., U.S. 

 National Museum; Stillman Wright and Elmer 



Table 7. — Length distribution and percentage of 221 shrimp, Macrobrachium vollenhovenii and M. macro- 

 brachion, culled from the commercial catch in the lower St. Paul River, Liberia, August 4, 1952 



Species and 



total length 



(5-mm. intervals) 



Male and 

 female, with- 

 out eggs 



Females with 



green or red 



eggs 1 



Females with 

 brown eggs 



Total ovigerous 

 females 



Total shrimp 

 examined 



No. 



% 



No. 



% 



No. 



% 



No. 



% 



M. 



Total 122 



55.1 



45 



20.3 



28 



12.6 



73 



32.3 



vollenhovenii: 



50-54 



55-59 



60-64 



65-69 



70-74 



75-79 



1 



0.4 



4 



1.8 



5 



2.3 



6 



2.7 



8 



3.6 



1 



0.4 



0.5 



0.5 



Total 25 



11.2 



0.5 



0.5 



No. 



195 



26 



% 



M. macrobrachion: 























40-44 



2 



0.9 



— 



— 



— ■ 



— 



— 



— 



2 



0.9 



45-49 



12 



5.4 



7 



3.2 



2 



0.9 



9 



3.2 



21 



9.5 



50-54 



31 



14.0 



27 



12.2 



16 



7.2 



43 



19.5 



74 



33.5 



55-59 



35 



15.8 



10 



4.5 



10 



4.5 



20 



9.1 



55 



24.9 



60-64 



27 



12.2 



1 



0.4 



— 



— 



1 



0.5 



28 



12.7 



65-69 



10 



4.5 



— . 



— 



— 



— ■ 



— ■ 



— . 



10 



4.5 



70-74 



5 



2.3 



— 



— 



— 



— 



— 



— 



5 



2.3 



88.3 



1 



0.5 



4 



1.8 



5 



2.3 



6 



2.7 



8 



3.6 



2 



0.9 



11.8 



1 Eggs in early stages of development are green in M. macrobrachion and red in M. vollenhovenii, while eggs 

 in advanced stages of both species are brown. 



12 



