NO. 1G50. AMERICAN SPECIES OF SYNALPHEUS—COUTIERE. 7 



a \ CarpoceiMte short, arisins nearly opposite the median antennulary article ; 

 basal article of the antenniile equal to the following, or 1.5 times as long, 

 or more; i)almar border of the larjie cheliped unarmed. 

 &\ Carpocerite three times as Ion;; as wide. 

 g\ Meropodite of the tliird pair more than o.5 times as long as wide; large 

 chela 2.9 times as long as high; auteuiuil spine equal to the carpo- 

 cerite S. lockinfftoni. 



e*. Meropodite of the third pair less than 3.5 times as long as wide; large 

 chela 2.5 times as long as high; antennal spine longer than the 



carpocerite, slender S. latastci tenuisinmi. 



& ^ Carpocerite less than three times as long as' wide ; antennule thick, 

 scarcely four times as long as wide; meropodite of the third pair three 



times as long as wide /Sf. hitd.stci. 



l)\ Carpocerite more than three times as long as wide; meropodite slender, 

 five times as long as wide; spine of the scaphocerite surpassing tbe 

 antennule 8. paulsono'ides. 



BREVICARPUS group. 



a \ Carpocerite cylindrical, slender, at least four times as long as wide ; antennal 

 scale from 5.5 to G.4 times as long as wide; basicerite almost unarmed 

 above; meropodite of the third pair from 4.25 to 4.5 times as long as 

 wide; carpus of the second pair from ten to fifteen times as long as 

 wide; telson 2 to 2.2 times as hmg as wide distally. 

 h^. Lateral si)ine of the scaphocerite scarcely surpassing the scale; frontal 

 teeth equilateral, short; eggs of large size, producing mysis. 



S. brcvicnrpus. 



6^ Lateral spine of the scaphocerite long and slender; frontal teeth as 



long as wide at the base; rostrum with concave margins; eggs small, 



producing zoese S. brciicarpus gueiini. 



a ^ Carpocerite swollen, from 3.5 to 3.7 times as long as wide ; antennal scale 



from 7 to 8.5 times as long as wide; carpus of the second pair less than 



ten times as long as wide; meropodite of the third pair 3.4 to 4 times 



as long as wide; telson l.S times as long as wide distally; larvfe zoeiP. 



&\ Antennnles at most five times as long as wide; rostrum as long as the 



lateral teeth of the front. 



c\ Frontal teeth short, equilateral. 



fZ\ Superior spine of the basicerite feeble, as wide as long, that of the 

 scaphocerite shorter than the carpocerite; small claw with elon- 

 gated fingers, 2.8 times longer than wide S. minus. 



d^, Superior spine of the basicerite twice as long as wide, that of the 

 scaphocerite equal to the carpocerite; small claw with short fin- 

 gers, 2.G times as long as wide 8. minus haJiicnsis. 



G^. Frontal teeth long, a little concave; carpocerite very swollen, from 

 3.2 to 3.5 times as long as wide; scaphocerite short; hooks of the 



dactyls often equal 8. minus antiUcnsis. 



J)'. Antennules more than five times as long as wide; rostrum shorter and 

 narrower than the lateral teeth. 

 c\ Carpocerite 3.5 times, meropodite of the third pair 3.4 times, as long 



as wide 8. digueti. 



c^ Carpocerite 3.2 times, meropodite 3.25 times, as long as wide. 



8. digueti ecuadorensis. 



