Mr. II. J. Carter on the Organisation of Infusoria. 221 



gjcneral surface; a property which wc have seen to exist in all 

 parts ol" the posterior bulb. 



This pretty and interesting, though minute, Actinoid was found 

 at Torquay in July by Miss Pinchard, an aceoniplished student 

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

 me in its own native nidus, — an okl Saxicava's biurow in the 

 limestone rock, out of which its fore-parts projected (see tig. 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. 



EXPLANATION OF PLATE IX. 



Fig. 1. Edwardsia curnea : natural size. 



Fiff. 2. Ibid. (raagulHed), in the act of [jrotruding. 



Fig. 3. Ibid, (magnified) ; the anterior column protnided an<l expanded. 



Fig. 4. Ibid, (magnified); the posterior bulb protruded. 



XXI. — Notes on the Freshwater Infusoria of the Island of Bomtjay. 

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

 Surgeon II.C.S., Bombay. 



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

 yellow colour, and fixed to one side of a transparent ca])sulc, 

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

 causes the latter to a])])car as if surrounded by a narrow pellucid 

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

 phrys, Spotigilla, Astasia (fig. 45 b), and Euglena (tigs. 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 Dijflagia protriformis it cannot of course be seen, from 

 the thickly incrustcd state of the test ; but in a smaller and loss 

 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 Euglypha it can only occasionally be distinguished; 

 while in Arcella vulgaris (Ehr.) it is constantly double and 



