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Cyclograpsus whitei Milne-Edwards.
Cyclograpsus whitei Milne-Edwards, Ann. Sci. Nat., vol. 20, p. 197. 1853.
— Filhol, Mission de l'Ile Campbell, p. 391. 1885.
Cyclograpsus lavauxi (part) Miers, Cat. Crust. N.Z., p. 41. 1876.
— (part) Haswell, Cat. Crust. Austr., p. 104. 1882.
— Chilton, Trans. N.Z. Inst., vol. 43, p. 560. 1911 (not of Milne-Edwards).
This species was very briefly characterized by Milne-Edwards, and disallowed by Miers, who (without seeing specimens) suggested that it was only a variety of C. lavauxi. Filhol has admitted the validity of the species by stating that specimens are in the Paris Museum, for he had access to the collections there; but he has shown such deference to the determinations of Milne-Edwards that this is hardly an additional argument in favour of the validity of the species. It is therefore satisfactory to be able to decide quite definitely upon this point, from a study of our own specimens.
C. whitei is a valid species, and the distinctive characters may be conveniently stated in the form of a comparison with the commoner species.
| C. lavauxi. | C. whitei. | |
|---|---|---|
| Regions | Regions defined; front with longitudinal furrow. | Regions not defined; carapace quite smooth except for faint transverse groove in gastric region. |
| Front | Strongly depressed | Still more depressed; at right angles to carapace. |
| Carapace | Length 16 mm., breadth 21 mm., ratio 1:1.3 (somewhat variable). Sometimes broader in front than posteriorly, especially in female, but also variable. | Length 18.5 mm., breadth 22 mm., ratio 1:1.2; slightly narrower in front than posteriorly. |
| Edge of carapace | Finely granulated. | Smooth. |
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| C. lavauxi. | C. whitei. | |
|---|---|---|
| Orbits | Small but well incised; outer corner raised to a point. | Very small; not forming a raised point at the outer corner; eyes very small. |
| Third Joint of external maxillipeds | Subquadrate; length scarcely exceeding breadth; distal end truncate. | Elongate, length nearly 1½ times breadth; distal end distinctly produced on inner side. |
| Legs | Slender, compressed. | Robust, very slightly compressed. |
| Tarsi | Long, slender, with six lines of short and very dark hairs running whole length of tarsus. | Short, thick, with hairs only at the tip, but with punctulated lines through the whole length. |
Of these characters, those relating to the orbits, maxillipeds, and tarsi are the most distinctive. There are other differences besides the above; thus in the ambulatory legs, the longitudinal ridge on the front and hinder surfaces of the last three joints are less distinct than in the case of C. lavauxi; and the same applies to the granulated ridge on the upper edge of the merus of the same limbs. The penultimate joint of the male abdomen is not as swollen as in C lavauxi. The arm of the female has a few long hairs on the anterior edge of the carpus and merus. The dimensions of the tarsi may be indicated from those of the last pair of legs; in C. whitei, the length of the tarsus is equal to the breadth of the merus, but in C. lavauxi the ratio is 1½ (Filhol's figure is inaccurate in this respect).
The fingers of the hand of the female leave only a small gap when closed; they are regularly and prominently denticulate. The hands of the male are larger, and the fingers leave a wide gap at the base; they are sometimes denticulated as in the female (3 of our specimens), but usually the teeth, are obsolete (4) or absent (5).
Neither species is “entirely destitute of hairs,” as Miers states. There are short but distinct hairs on the edges of the abdomen and sternum, especially in the female, on the maxillipeds (densely at the base), and over the whole pterygostomial and subhepatic regions.
Locality.—N.Z. (Miers).
Our New Zealand specimens were placed in a Jar containing C. lavauxi before it was noticed that the two species were distinct, so that the locality or localities are not known; but from MSS. notes we infer that our specimens came from one of the last five localities quoted under C. lavauxi.
Distribution.—Kermadecs (Chilton, l.c.).