193 



and it is this feature which induced him to regard his specimens as closely related to " Carci- 

 noplax" vestita (de Haan), whereas I observed only a row of feathered hairs along upper 

 and under border and none on the surface of the chela; in the "Challenger" specimens of 

 MiERS the chelae are said to be pubescent on the upper part of the palm and the base of the 

 dactylus, and the carpopodite presents an obsolete tooth on the outer margin. Apart from the 

 quite different shape of the abdomen in the present species and in that of de Haan, the shape 

 of the carapace in the former, with its prominent antero-lateral teeth, its roughly-quadrangular 

 outline and its marked sculpture certainly affords .evidence of the distinctness of these two 

 species; besides '' Carcinoplax" vestita grows to a much larger size. 



Whether Miers' species is identical with ''Eucrate" sexdentata Haswell must remain 

 uncertain, on account of Haswell's quite incomplete diagnosis. 



The "Alert" specimens were obtained in the Arafura Sea, from a depth of 32 — 36 

 fathoms, those of the "Challenger" in the Japanese Seas, from 10 — 15 fathoms. These examples 

 were only slightly larger than that of the "Siboga" e.xpedition. 



Dimensions in mm.: 



Distance between external orbital angles 5.2 



Breadth of front between eye-stalks. . , 2.5 



Greatest breadth of carapace (between tips of posterior lateral teeth). . 7. — 



Length of carapace 5.2 



Length of meropodite 1 / ' 5. — 



Breadth of meropodite J I 0.75 



Length of carpopodite along anterior margin I I 2. — 



T ,, r .-,1 , ■ ■ / of penultimate pair of legs ( 



Length of propodite along anterior margin ° 1 2.5 



Breadth of propodite I | 0.5 



Length of dactylus ) I 1.15 



Speocarcinus Stimpson. 

 1862. Speocarcinus Stimpson. Ann. Lye. Nat. Hist. New York, v. 7, p. 59. 



This genus now contains four species, enumerated on p. 189, which in their outer aspect 

 much resemble R/iizopinae, on account of their vaulted carapace, the small eyes, partly concealed 

 in upper view, and long, hairy legs. In the Rhizopinae, however, the surface of the carapace is 

 scarcely or not at all sculptured and the lateral margins, if at all, are obscurely notched, never 

 toothed; the eye-peduncles, which are very short, are usually fixed, not mobile and nearly 

 completely concealed in dorsal view of the animal, and the abdomen of the cf is very narrow 

 at its base, covering one-half or one-third only of the space between the last pair of legs, 

 whereas in Speocarcinus the carapace is sculptured and toothed, the eye-stalks are mobile, and 

 the abdomen of the cf occupies the greater part of the last segment of the sternum. 



Miss Rathbun, who examined all the species and herself made known three of them, 

 has never provided a key to discriminate them. As to myself, I am unable to do so, partly 

 because the description of one species (S. californiensis) is inaccessible to me, and partly on 

 account of the general deficiency of the diagnoses. I can only say that in S. granulimanus, 

 from Lower California, the outer orbital angle is followed by three antero-lateral teeth, separated 



45 



