64 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 5 



outer antennal spines. Pterygostomian ridge tuberculate; one suborbital 

 and two subhepatic spines and a paving of subbranchial spinules. An- 

 tennules folding almost longitudinally, fossae large, incompletely di- 

 vided. Merus of third maxilliped deeply notched for insertion of palpus, 

 outer external angle produced and scalloped; inner border of ischium 

 spinulous and hairy. 



Cheliped of female with merus and carpus tuberculate and spinu- 

 lous, merus with an upper row of three or four, an outer row of six, 

 and an inner row of two or three tubercles. Manus with a cluster of 

 half a dozen rounded granules at basal end of superior surface and two 

 or three at base of outer surface; hand otherwise smooth and bare. 

 Fingers of female weak and toothless, meeting with a slight gape. 



Ambulatory legs with a double row of spinules above; carpus 

 grooved; propodus cylindrical; dactylus with finely denticulate inner 

 margin, tip yellow, horny, incurving. 



Color in life: Frontal, gastric, and branchial regions deep hellebore 

 red ; cardiac and intestinal regions deep olive buff. A small spot of deep 

 olive buff at base of outer orbital tooth and a large spot at base of first 

 marginal tooth. Chelae deep olive buff; merus with two broad, irregu- 

 lar bands of hellebore red; carpus hellebore red; hands with lighter 

 bands of red and a band at base of fingers; distal half of fingers orange 

 yellow. Ambulatoiy legs banded as chela. (Petersen) 



Remarks: Because of its isolated position nearly 500 miles from 

 the mainland coast, Clarion Island, outpost of the Revilla Gigedo 

 group, has developed a unique fauna. A number of morphological 

 characters separate the proposed new species from M. sinensis Rathbun 

 (1892) of the Gulf of California, as shown by comparison with a long 

 series of the latter taken by Allan Hancock Expeditions, one of which 

 was compared by the writer with the type ( U.S.N. M. 16065). 



( 1 ) The carapace, while but slightly broader than that of sinensis, 

 is decidedly wider at the base, the posterolateral margin being 

 more nearly transverse. 



(2) The paving of the carapace is composed of much finer tu- 

 bercles and granules, there being approximately twice as many 

 raised prominences on any area examined. (See comparative 

 gastric regions, pi. 15, figs. 1 and 5.) 



(3) There is a fully developed third orbital spine, as against two 

 mentioned in the description of sinensis and the merest sug- 



