Boone, Crustacea, Cruises of "Ara" and "Alva" 209 



of specimens available, including those of the United States gov- 

 ernment collection, this variation occurring with equal frequency 

 among specimens from both east and west tropical America, and 

 being correlated with : (a) size of specimen ; (b) age and erosion 

 of existent carapace, which, owing to the burrowing habits of 

 the species, is subject to more than usual polishing by sand, etc., 

 and (c) to secondary sex characters, particularly with reference 

 to the chelipeds of large, old males, as compared with those of 

 young males and females. Several of the specimens examined by 

 the present writer showed the "inner angle of the frontal tooth" 

 less developed on the right side, corresponding to character 

 assigned to benedicti, but on the left side, more developed, 

 hence loevis. The anterolateral spines of recently moulted speci- 

 mens were invariably acuminate, also those of large old males 

 were frequently more acuminate than of smaller males and 

 females, irrespective of their geographic occurrence. Likewise the 

 chelipeds of large males have, in common with hundreds of other 

 species of crabs, more development apparent in the propodi and 

 dactyli than do young males and females. Specimens from Cuba 

 and Haiti, examined by the present writer, have in some instances, 

 chelae even larger than those ±rom the Perlas Islands shown in 

 plate 12. Some specimens from the Texas Gulf of Mexico coast, 

 examined by the writer, also have this character, and in two 

 instances, show a pearly granulation of the anterior of carapace, 

 which has been made much of as diagnostic of the questionably 

 valid R. ecuadorensis Rathbun. Most of the West Indian speci- 

 mens with fairly recently moulted carapaces have a distinct 

 rostral carinal line. The dactyl of the third ambulatory leg, meas- 

 ured critically, has no variation, except development due to 

 growth, through the entire series of specimens, from both east 

 and west coasts of the Americas, hence no specific value. 



References : Raninoides loevis lamarckiy Boone, L., Bull. Van- 

 derbilt Mar. Mus., 1930, vol. II, p. 48, pi. 12 ; Errata, p. A, 

 as R. loevis Latreille. 



Raninoides benedicti, Rathbun, M. J., Bull. CLXVI, U. S. Nat. 

 Mus., 1937. 



