STALK-EVED CRUSTACEA 227 



Subfamily II. Trichodactylinse. 



TricJiodactylince .... Rathbun, Ortmann. 

 Trichodactylns (genus) . . H. Milne Edwards. 



Carapace more or less rounded, very little trans- 

 verse, about as broad as long. Front gradually sloping 

 downwards, without superior ridge. The fourth joint 

 of the external maxillipedes triangular, apex of triangle 

 directed inwards ; the fifth joint joining it at the 

 upper angle. Terminal joint of walking legs without 

 spines. 



Synopsis of the Genera. 



A. Eyes very small, diminishing in size at terminal 

 half 



a. Carapace suborbicular ; lateral teeth, when present, 

 small, appressed. Lower margin of orbit and buccal 

 ridge unarmed, or feebly tuberculate. Last joint of 

 walking legs narrow, awl-shaped. — {Tric/iodactyhis.) 



B. Eyes not diminishing in size towards their 

 tip. 



b. Surface of carapace uneven, often with a blunt 

 ridge running transversely or obliquely across the 

 branchial region. Lateral teeth dentate or spiniform. 

 Lower margin of orbit tuberculate, with spines at inner 

 angle. Buccal angle usually not armed. Last joint of 

 last pair of walking legs flat, of the other pairs, styliform. 

 — ( Sylviocarcinus}) 



c. Carapace very convex antero-posteriorly ; lateral 

 teeth spiniform. Lower margin of orbit and buccal angle 

 usually armed with spines. Last joint of walking legs 

 narrow, flat. — {Dilocarcinus^ 



