Mr. H.J. Carter on the Organization of Infusoria. 221 



general surface; a property which we have seen to exist in all 

 parts of the posterior bulb. 



This pretty and interesting, though minute, Actinoid was found 

 at Torquay in July by Miss Pinchard, an accomplished student 

 of our marine natural history. This lady kindly forwarded it to 

 me in its own native nidus, — an old Saxicava's burrow in the 

 limestone rock, out of which its fore-parts projected (see fig. 2). 

 Though removed from its burrow for the purpose of examination, 

 it has lived several weeks in one of my small aquaria, expanding 

 at intervals (somewhat charily), and frequently adhering to the 

 glass by its posterior bulb. 



^baiflioq .xir EXPLANATION OF PLATE IX. 



Fiff. l.ESwardsia carnea: natural size. 



Fig. 2. Ibid, (magnified), in the act of protruding. 



Fig. 3. Ibid, (magnified) ; the anterior column protruded and expanded?., 



JV^r, 4. I6ic?. (magnified); the posterior bulb protruded. ■, 



_ _ : , ' 4 b'urf iUm 



XXI. — Notes on the Freshwater Infusoria of the Island of Bombay, 

 No. 1. Organization. By H. J. Carter, Esq., Assistant 

 Surgeon H.C.S., Bombay. ^,,1 



^ ''^i "^^ [Concluded from p. 132.] '"^^ "^ 



Nucleus. — By this term we shall understand, for the most 

 part, an organ situated in the outer portion of the sarcode, which, 

 when well marked, presents under the microscope the appear- 

 ance of a full moon (to use a familiar simile), with similar slight 

 cloudinesses (figs. \ d,2 e,^d). It is discoid in shape, of a faint 

 yellow colour, and fixed to one side of a transparent capsule, 

 which, being generally more or less large than the nucleus itself, 

 causes the latter to appear as if surrounded by a narrow pellucid 

 ring. In this state it is invariably present in Amoeba, Actino- 

 phrySf Spongillttj Astasia (fig. 45 h), and Euglena (figs. 46 a, &c.), 

 though difficult at first to recognise ; particularly in the two 

 latter families, where the pellucid space or capsule, at the bottom 

 of which it is situated, is often the only visible sign of its pre- 

 sence. In Difflugia proteiformis it cannot of course be seen, from 

 the thickly incrusted state of the test ; but in a smaller and less 

 incrusted species, which might be called D. tricuspis (from the 

 trefoil-form of the opening of the test) (fig. 80), as well as in 

 Euglypha, its position is posterior, and evident, from the large- 

 ness of the capsule, though the nucleus itself is so faint that 

 even in Euglypjha it can only occasionally be distinguished; 

 while in Arceila vulgaris (Ehr.) - it is constantly. ..double, , aij4 

 nsqotqlm'iohLr^ ^dj vd ba^ubo-iq noii:!jdhs im'ioqmoi 



