CAPRELLIDEA. gQQ, 



slender species, however, the second segment is often much longer 

 than the third and following. But, while this may be true of the 

 male of a species, it sometimes is not true, or but slightly so, of the 

 female. 



The ovigerous females are readily distinguished from males by the 

 plates beneath the third and fourth thoracic segments. But females 

 without eggs appear to be without this mark of the sex, and resemble 

 the males. 



There are, hence, hardly any characters which are with certainty 

 common to both sexes in a species. The occurrence of individuals at 

 the same locality, the similarity in the hairs of the antennae, and in 

 the form of the joints of the flagellum (not their number), and the 

 spines or tubercles of the body, are the most important characteristics 

 common to the sexes — yet, even in the spines, the sexes may differ. 

 In Caprellae, the articulation of the second pair of legs with the 

 posterior half of the thoracic segment in males, and with the anterior 

 half in females, appears to be a constant character. 



Genus PROTO, Leach. 



Proto elongatus. 



Corpus gracile, omnino inerme el inornatum. Caput antice rotundatum 

 segmento proximo fere duplo longius. Segmenta tlioracis 2dum, Stium, 

 Atum, 5tum, Qtumque oblonga et subaequa. Antennae, \rnae, dimidio 

 corporis parce longiores, flagello 8—10-articidato, paululo breviore 

 quam basis, articulis oblongis, setis paucis, brevioribus quam articuli. 

 Antennae, 2do3 basi lmarum vix longiores, flagello 4t-articulato, paulo 

 breviore quam articulus precedens. Manus lma oblonga, triangulata, 

 margine inferiore ad basin dente salknte armato, digito parce breviore 

 quam manus. Manus 2da elongata, palmd rectiusculd prope manus 

 basin dente acuto armatd, et maris dente alio versus apicem. Bran- 

 chiae, longae fere lineares. Pedes 3tii ^tive htis longiores. 



Body slender, without spines or tubercles. Head rounded in front, 

 about twice as long as next segment. Second, third, fourth, fifth, 

 and sixth thoracic segments subequal, oblong. Superior antennae 

 longer than half the body; flagellum hardly as long as base, eight 



203 



