OSACHILA LATA. 



33 



ance. 



branchial; the surface of all of these protuberances is tuberc'ulate, tlie 

 tubercles coarsely punctate, the surHice between the protuberances smooth 

 and coarsely punctate. Front prominent, bilobed, the lobes separated by a 

 completely closed fissure ; frontal margin thick, rounded, with two punc- 

 tate tubercles ; anterodatcral margin of carapace sharp ; behind the pointy 

 where the subhepatic ridge joins this margin it is divided into five obtuse 

 lobes, each of which is denticulate ; postero-lateral margin single, tubcrcu- 

 lated; posterior margin narrow, concave ; two transverse rows of low tuber- 

 cles on the hinder part of the carapace anterior to the hind margin. Beneath, 

 tlie subhepatic region and the surface of the outer maxillipeds, sternum and 

 abdomen are tuberculatcd and heavily pitted, presenting an eroded appear- 



Subbranchial area smooth. The merus of the chelipeds is tuberculate 

 alon"- the upper edge and outside of it ; carpus tuberculate externally, distal 

 and superior margin produced to a cristiform tooth which continues back 

 upon the carpus the crest of the superior border of the propodus ; propodus 

 tuberculate on outer flxce, the tubercles largest above, superior border forming 

 a sliglit denticulate crest which is split into three indistinct lobes ; lower margin 

 of hand ornamented with a row of low, but rather large tubercles. The edges 

 of the ambulatory limbs are slightly cristate; dactyh pubescent on distal 

 portion. There are traces of transverse red bands on the ambulatory legs. 

 Lcno-th, 24.5 mm., breadth, 32 mm. 

 J Station 3427. 80 fathoms. 1 male. 



In this species there is a cresccntic depression on the margin of the 

 pterygostoniian region in front of the base of the chelipeds, leading into 

 the branchial chamber ; this depression is much more strongly marked than 

 in Ilepahis or in OsacJdla tuherosa Stimps. [0. acuta Stimps. and 0. stmpsonii 

 Studer I have not seen). The third, fourth, and fifth abdominal segments 

 in the male are fused into one, as in Ilepahis and 0, tuherosa. In the genus 

 OsacUla the apex of the merus of the outer maxillipeds is notched or con- 

 cave^ leaving an opening into the excurrent branchial canal when the outer 

 maxillipeds are 'closely applied to the buccal area. This orifice docs not 

 exist in Hepatus or in Acfwomorpha Miers, a genus which must be closely 

 allied to OsacMla. The second and third segments of the antenna3 are present 

 in Omcliila^ but only as the merest rudiments. 



Three species of Osachila have been previously described : 0. tiibcrosa 

 Stimps.* from the Antilles and off Cape Hatteras, 36-164 fathoms ; 0. acuta 



* Bull. Mus. Comp. Zr,ol, TI. 154, 1870. 



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