100 



KNOWLEDGE. 



[May, 1001. 



the statement to mean that this is the measnre, oi- 

 estimate, of the average height of the greater waves 

 of which some were encountered and a number seen 

 during the storm, and I see no reason to quarrel with 

 such a mode of statement. It admits, liowever, of an 

 apparent discrepancy of probably 100 per cent, between 

 the values assigned to the height of ocean waves accord- 

 ing to whether we adopt the concrete or the abstract 

 notion of a wave. 



GIANT OSTRACODA: OLD AND NEW. 



By the Rev. Thomas R. R. Stebbing, m.a., f.r.s., f.l.s., etc. 



As students ai-e aware the species of Entomostraca are 

 for the most part very inconspicuously conspicuous, and 

 among those of them which are thus notable not for 

 being very large but for being very little the Ostracoda, 

 if not absolutely foremost, are certainly well to the front. 

 Recent researches, however, have shown .that in this 

 group as in othei's an astonishing disparity of size may 

 separate exceptional members of it not only from the 

 minutest fomis but from the average dimensions. 



In 1880, Dr. G. S. Brady in the first volume of the 

 " Challenger " Zoological Reports described a new genus 

 and species from the South Pacific under the name 

 Crossophorus imjyerafor. After giving the length as 

 " ^ of an inch (8.4 mm.)," he refers to it with a kind of 

 ejithusiasm as '" this noble species, certainly the largest 

 of the known Cypridinidas." The family in question 

 was already itself distinguished among the Ostracoda 

 by having representatives which could boast of some 

 such exorbitant length as the sixth of an inch. By 

 abruptly doubling this the Crossophori/.s would pro- 

 bably attain a bulk about eight times that of its largest 

 known competitor. In 1896 Drs. Brady and Norman 

 described another specimen, assigned to the same species, 

 with a length of 7 mm. Though both specimens were 

 reported from very great depths of nearly equal tem- 

 perature, it is remarkable that the first, a male, was 

 taken a little to the east of New Zealand, the second, a 

 female, " was procured by the ' Porcupine ' Expedition 

 of 1869, in the Atlantic, west of Donegal Bay, Ireland." 

 The same length of 7 mm. is reached by CijrlaMerope 

 Jieiuleraoni, Brady, 1897, which Mr. Henderson, of the 

 Christian .College, Madras, brought to light by dredging 

 in Madras Harbour. 



At the close of last year a new species, Asferope 

 artbiiri, 8 mm. long, was described among the Crustacea 

 brought by Dr. Arthur Willey from the South Seas. 

 In regard to this interesting form it may be mentioned 

 that before the specific name had been given, some of 

 its appendages were figured in the volume of Know- 

 ledge for 1899, in the course of an essay dealing with 

 the general structure of the Ostracoda (Vol XXII 

 p. 31). 



In 1898 Professor Sars described a new genus and 

 species under the title " Mec/nlocyprif; 2irmceps, a 

 gigantic fresh-water Ostracod from South Africa." This 

 species, from a pond near Capo Town, attains a length 

 of 7.30 mm., while apparently not full grown, and,'' as 

 it belongs to the family Cyprididae, in which the forms 

 are usually very small, its " truly gigantic size " is even 

 more surprising than that noted in the preceding 

 instances. In 1900 M. Jules Richard reports a " Gujanto- 

 <-ypri«" a\w\ii lo mm. in diameter, as having been dredged 

 by the Prince of Monaco from a great depth off the 

 Azores. 



These examples, however, do not exhaust the po.=si- 



bilities of the Ostracode group, for Dr. Gilchrist in 

 December, 1899, while conducting marine investigations 

 on board the South African Government vessel the 

 " Peter Faure," and dredging in 90-100 fathoms off 

 Ca2)e St. Blaize, obtained specimens of Ostracoda which 

 much surpass the dimensions above quoted. The speci- 

 mens were speedily forwarded to me by Dr. Gilchrist, 

 and were examined at once. That they have not been 

 sooner recorded is due in part to the well-founded and 

 growing dislike of preliminary notices, and in part to 

 my apprehension that there had been made else- 

 where an earlier discovery of a magnificent Ostracode, 

 which might prove to be the same species. After 

 talking the matter over with a scientific friend, I am 

 now induced to think with him that tlie case is one of 

 exceptional interest, in regard to which publication 

 should no longer be delayed. The fact is that the speci- 

 mens have a length of 15.5 mm. by a height of 12.5 mm., 

 so that the noble Croxsoplwrus imperatiir and the truly 

 gigantic Meijahicyprin princep^ are positively dwarfed 

 by the comparison. 



The new species, for which I jjropose the name Crosso- 

 phorus africanus, has its generic position pretty well 

 assured, since, among other points, to quote Brady and 

 Norman, " the peculiar arrangement of the armature 

 of the caudal laminae is unlike that of any other known 

 genus." But the new species, though agreeing in the 

 general plan of arrangement, differs in detail, having 

 only five principal spines instead of the seven which 

 the smaller species displays. The mandibles have the 

 bifid masticatory appendage, found in one or two other 

 genera, but not there densely setulose as it is here. 

 The maxillipeds have the large sub- triangular lamina, 

 fringed with plumose setae, and ending with a small 

 lobe also fringed. This lobe is peculiar to Crossophorus, 

 but it is much less clearly developed in the Irish speci- 

 men of C. imperator than in the New Zealand specimen. 

 From the Irish C. imperafor the new African species is 

 strikingly distinguished by the apical part of the 

 vermiform limb.* Here it forms a regular mouth, one 

 jaw ending in a tooth, which confronts in the other a 

 neat circlet of denticles. In the Irish specimen the 

 tooth confronts ''several (six?) finger-like curved pro- 

 cesses which are ciliated on the edges." In the New 

 Zealand specimen the limb is described as being " al- 

 most exactly like that of Cypridina." The result of 

 these comiaarisons is to make me believe that we have 

 to do with three specimens of the genus, first, the 

 original Crossophorus imperator, Brady, from the 

 Pacific ; secondly, the species described by Brady and 

 Norman, of nearly the same size, from the North 

 Atlantic, which may be distinguished as Crossophorus 

 imperialis ; and thirdly, the new African species, 

 Crossophorus africanus. For the latter detailed draw- 

 ings have been already prepared, and these with accom- 

 panying description will, I hope, in due time more 

 fully explain, and adequately justify this preliminary 

 decision. 



That an iso]jod which I find parasitic within the new 

 species is itself likewise new may be affirmed without 

 hesitation. The name I propose for this is CijproniscKs 

 crossophori. It bears a strong resemblance to the much 

 smaller Cyproin'scns cypridimr, Sars. Its distinctness will 

 be apparent in the account and figures which are reserved 

 for their a]ipropriate ]ilace in the " Marine Investigations 

 of South Africa," published by the Cape Government. 



* For the general appearance of this strange appendage, see the 

 figures in Knowledqh, Yol. \XIT., pp. HO, 31. 



