1902.] OSTRACODA FROM COCOS KEELIXG ATGLL. 229 



which have occurred in abyssal deposits, such as B. milne-edwards'd 

 and B. crosskeiana. They are all, however, of far more frequent 

 occurrence in shallow-water dredgings. A few of the species 

 have a wide geographical range, as B. milne-edicardsn, B. acanthi- 

 gera, and B. crosskeiana, which are also northern species. Of the 

 10 species of Gythere two are known from northern areas, namely, 

 C prava and C. stimjysoni. Another species, C. dlctyon, is moi'e 

 often found in deep water, being recorded from fifteen out of 

 twenty-five of the ^ Challenger ' dredgings at depths of 1000 

 fathoms and more. The remainder are well known from shallow- 

 water dredgings. The genus Loxoconcha is represented by four 

 species, three of which have a fairly wide range, namely, L. alata, 

 L. honoluliensis, and L. anomala. Thei-e are three species of the 

 genus Xestoleheris^ two of which have a wide range ; one of them, 

 X. depressa, is also common in dredgings ofi' the Bi-itish coast, 

 from the North Atlantic, and also as a post-Tei-tiaiy fossil from 

 Scotland, Ireland, Norway, and Canada. The only species of 

 Cytheropteron recorded here, namely G. longlcaudatum, was origi- 

 nally described by Dr. G. S. Brady from material dredged in the 

 Fiji group. 



Description of JSfetv Species of Ostracoda. 



(The specimens wei'e not preserved sufficiently well to enable 

 the organisms to be examined.) 



Cytherideis andrewsi, sp. nov. (Test-fig. 27.) 



Carapace suboval, elongate, somewhat arcuate and compressed. 

 Dorsal margin, in side view, lather irregularly curved ; ventral 

 niai'gin concave and sinvious. Anterior extremity produced ; 



Text-fiff. 27. 



Cytherideis andrewsi. 

 a, right valve, lateral view ; h, edge view ; c, end view. X 42 linear. 



posterior evenly and broadly rounded. Edge view compi-essed 

 ovate. End view subcir-culai-. Surface of the carapace covered 

 with fine pittings ; and the nfiviscle-spots in the median area 

 disposed in rosette- form. Length '57 mm. 



Oocos Island, lagoon ; very lare. 



This species difiers fi-om C. Icevata G. S. Brady in form and 

 also in the surface- markings on the carapace itself ; but it is 

 eAadently allied in some respects. 



