213 



Dr. J. Gwyn Jeffreys on the [June 15^ 



in which it assumes a dorsal position (e. g. Cassidulus, Echinohrissus, Clypeo- 

 pagus, and other genera) it is always sunk in an anal groove. This new 

 and most interesting form will be named Aerope rostrata by Sir Wyville 

 Thomson*. In this dredging were also procured a specimen of Leucon 

 longirostris, G. 0. Sarst (which was described by him from a fragment 

 procured in the ' Josephine ' Expedition), Leucon serratus, Norman, a new 

 Diastylis (D. armata)^ and five undescribed Isopoda. This dredging was 

 also by far the most important as regards the Foraminifera. The 

 Olohigerince here presented an entirely different aspect from that of 

 those usually met with — so much so that they might have been taken to 

 belong to a different species ; the segments have a comparatively com- 

 pactly compressed appearance, very different from the rounded, swollen 

 outline so characteristic usually of the chambers of Glohigerina bulloides. 

 The ooze, moreover, has a reddish tinge, and contains a large number of 

 remarkable arenaceous Foraminifera, and more Polycystina than are 

 usually met with in North- Atlantic dredgings. From the peculiar 

 appearance of the Glohigerince and the character altogether of this 

 dredging, it would seem that we have here the commencement of that 

 transition state of the sea-bed between the ' Glohigerina- ooze' and the 

 * E-ed ClayJ' which has been termed by Sir "Wyville Thomson "Grey 

 ooze," and has been found by the ' Challenger ' Expedition to constitute 

 the bottom at depths of about 2500 fathoms in the South Atlantic. I 

 am thus led to infer that the peculiar form of the Glohigerince is dependent 

 partially or wholly upon incipient decomposition. The arenaceous Fora- 

 minifera are an extraordinary assemblage. They embrace no less than 

 eighteen distinct and well-marked forms, most of the more conspicuous 

 species found in the ' Porcupine ' Expedition, viz, Rhabdammina, Pilulina, 

 what Carpenter has called ' nodosarine,' ' moniliform,' ' nodosarine 

 No. 2,' ' globigerine,' ' orbuline,' and ' orthocerine ' Lituolce §, and 

 other forms. With these there are others which have not been before 

 observed, one of which must not be passed without notice. The genus 

 AstrorTiiza was constituted by Sandahl|| for the reception of a large flat 

 disk -like E^hizopod, having a test which consists of extraneous matter 



* When this description was read I had suggested a name for the present species ; 

 but having since learnt from Sir Wyville Thomson that it has also been procured in 

 the ' Challenger ' Expedition, I gladly adopt the above name, under which I found that 

 he was about to describe it. 



t Beskrivelse af de paa Fregatten Josephines Expedition funde Oumaceer, 1871, 

 p. 42, pi. XV. fig. 75. 



\ Proc. Eoy. Soc. 1874, vol. xxiii. p. 39 et seq. 



§ See Carpenter, 'The Microscope,' 5th edit. 1875, pp. 531-535, and woodcuts. 



II Ofversigt af Kong. Yet. Akad. Forhand. 1857, p. 301, pi. iii. fig. 526. The same 

 species has since been described by Bessels, Jenaische Zeits. fiir Naturwiss., heraus. von 

 der med.-natur, Gresellschaft zu Jena, 1857, p. 265, pi. xiv., under the name Haecke- 

 lina gigaoitea ; and by Schultze, ' Jahresbericht der Commission zur wissenchaft. TJnter- 

 suchung der deutschen Meere in Kiel fiir 1872-73,' pi. ii. fig. 10, under the name Astro- 

 discus arenaceus. 



