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Description

“Cirolana Venusticauda, n. sp.

 

1843. ? Cirolana sculpta (not Milne,-Edwards)„ Krauss, Die siid­afrikanischen Crustaceen, p.66.

 

Body about thrice as long as broad, by help of antennae and uropods nearly parallel-sided. Head much broader than long, not deeply immersed in peron, hind margin less wide than the slightly arched front, which has a well-marked process between the first antennae. First peron segment the longest) with hinder angles strongly rounded, the front ones squarely produced forward. Hind margins of the first four segments of peron and first of pleon smooth, the rest tuberculate, almost impercep­tibly on fifth peron segment, on the others successively with greater prominence, the fifth pleon segment having also on each side of the centre a strong tubercle in advance of the hind margin. The telsonic segment carries anteriorly a median carina begin­ning with a small tooth or prominence and ending in a large one, this being followed by two pairs of tubercles, of which the surface has in addition one or two at the base on each side of the carina, and many of -various sizes along each margin. The slightly sinuous sides, where free from the uropods, are fringed each with seventeen spines in sets of six and eleven, interspersed with short plumose seta, the narrowly rounded apex having a similar arma­ture of four spines and accompanying set. Of the second and third peraeon segments, the side-plates do not reach the hind margin of their respective segments, and in the former case are narrower behind than in front ; in the other segments the side-plates have the hind margin produced backward, and agreeing as to sculpture with the hind margin of the segment, those of the seventh overlapping the first two segments of the pleon. The third pleon segment is the widest, and the fourth is wider than the fifth.

 

The eyes are dark in formalin, roughly rounded, of moderate. size, with numerous small components.

 

First antennae—The peduncle is clearly three-jointed, shorter than the flagellum, which has seventeen joints furnished with hyaline filaments.

 

Second antennae—The first three joints of the peduncle are short, the fifth is longer than the fourth; the flagellum, about twice as long as the peduncle, attains to thirty-one joints.

 

The frontal lamina surmounting the epistome widens to the convex anterior border, from which it bends to meet the rostral point with an angular termination.

 

The mouth-organs are in tolerably close agreement with what is usual in the genus. In the first maxillae attention may be called to the little projecting horn on the outer side of the inner plate. Such a process is figured by Hansen for Cirolana borealis Lilljeborg, but not for Cirolana elongata Milne-Edwards, nor for his own Cirolana minuta, nor do I find it in Cirolana orientalis Dana, which has in its place a minute spine, in agreement with Cirolana japonica Hansen; the process is feebly developed in Cirolana pleonastic and Cirolana albicaudata, which I have recently described.

 

First gnathopods—These are rather robust, the fourth joint fully as broad as long, with two rows of spines along the inner margin, the short trianglar fifth joint underriding the sixth and having its base deeply imbedded in the fourth. The finger is shorter than the sixth joint, and as in all the trunk limbs has a short, dark-coloured nail, preceded by a small spine, which gives a biunguiculate appearance to the joint.

 

Second gnathopods—The spines on inner margin of fourth joint are arranged in two sets separated by an unarmed interval; the fifth joint is small, but does not underride the sixth, nor is it imbedded in the fourth; the sixth joint is much less stout than in the preceding pair.

 

Peraeopods-The first pair is similar to the second gnathopods. The other four pairs have the joints longer, especially the last two pairs which are subequal. There are no plumose setae on these limbs, but spines at the apices, and a few on the inner margins of the third to sixth joints.

 

Pleopods—The rami are broad in all of them.

 

Liropods—The peduncle is produced rather beyond the middle of the telsonic segment, but not quite to the middle of the inner ramus ; this ramus is very broad, and reaches beyond the segment, its margin, except near the base, being closely fringed with spines and set; the outer ramus, though about as long as the inner, does not reach nearly so far back, and is much narrower, but with similar armature. Colour, in formalin, cream, with symmetrical brown markings on upper surface, but not on under surface or on appendages, except the uropods. Length, 15 mm., or a little less or more.

 

Locality:—Table Bay, and from " Red Bait" (a large Ascidian), Somerset West, shore.

 

Krauss, loc. cit., under C. sculpia, M.-Edw., says. "A species distinguished by the exceedingly pretty marking of the abdomen, which I have found in Table Bay. Yellowish green, with black speckles and spots. Length, 6 lines." Herkiots in 1851 merely mentioned the name on Krauss's authority. Hansen doubts the identification, and is disposed to think, from the strong sculpturing of the pleon, that Milne-Edwards's species may be a Corallana. Milne-Edwards thus describes his C. sculpta:—“Head much broader than long, scarcely narrowed anteriorly, and little immersed in the thorax. Margin of the last thoracic rings and of the rings of the abdomen finely denticulate. The last segment of the abdomen furnished with a conical tooth on the median line, with a multitude of little crests and ending behind acutely. Feet feeble, and scarcely hairy. Terminal plates of the uropods almost of the same size and apically acute. Length, about 9 lines. From the coast of Malabar."

 

The description of the uropods will not at all suit the present species, and the distance of habitat does not encourage the hypothesis of misdescription. Milne-Edwards also says that in his species the head is scarcely narrowed in front; in the South African species it is plainly widened. The new specific name for the latter alludes to Krauss's remark upon the beautiful marking of the pleon.”

 

 

(Stebbing, 1902: 49-52)

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Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

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