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PACIFIC SCIENCE, Vol. XXII, October 1968 
Fig. 1 . Microdeutopus schmitti Shoemaker, salinas bay, costa rica. $ : a, paragnaths ; d, peraeopod 1 ; 
j, peraeopod 2; 1, ventral surface of peraeon segments 3-6. 
Microdeutopus hancocki sp. nov. salinas bay, costa rica. $ Holotype: b, peraeopod 1. $ Paratype: e, 
uropod 3; f, paragnaths; h, peraeopod 2; telson; k, ventral surface of peraeon segments 3-6. bahia honda, 
panama. $ Paratype: g, peraeopod 1 . salango island, Ecuador. $ : c, peraeopod 1 . 
In view of the magnitude of these characters, 
which always occur in combination, present 
material is designated as a new species, for 
which Microdeutopus hancocki sp. nov. is 
proposed. This is further justified since the 
form often occurs together with M. schmitti 
in the same sample in the type locality at 
Salinas Bay. In samples from Ecuador, Panama, 
and Galapagos, M. hancocki occurs alone, and 
specimens from the first two of these localities 
agree with the type material. Specimens from 
Galapagos are smaller and more delicate than 
the types, with the antennules and antennae 
relatively longer (about half the body length), 
and the basipodite of the first peraeopod not 
greatly expanded antero-proximally. In other 
respects, however, they agree with type speci- 
mens, and are here considered as a variant of 
M. hancocki. 
Females which occur with male M. hancocki 
in Panama and Galapagos samples resemble 
female M. schmitti, but differ from the latter in 
having the carpopodite of the first peraeopod 
smoothly rounded and lacking a tooth on the 
posterior distal angle. In M. schmitti females, 
one or more carpal teeth develop at an early age 
and are clearly discernible in specimens of 3.0 
mm body length, whereas, in Panama specimens 
considered to be M. hancocki, no tooth is pres- 
ent, even in females 4.0 mm long. Similar fe- 
males occur among M. schmitti females from 
Salinas Bay, and it is assumed that these are also 
the females of M. hancocki sp. nov. For practi- 
cal purposes, since separation of M. hancocki 
