488 MEMOIRS OF THE UNIVERSITY OB^ CALIFORNIA 



DiAGxosis. — A large species with rotund body, truncate posteriorly; its 

 length ].4 transdiameters ; epicoue flattened, small apical horn present; ocellus 

 simple, protuberant; lens sj^herical, with red flattened hemispherical pigment 

 mass; extended prod four tiaies length of body. Length of body a1)out 100/^. 

 Mediterranean off Sorrento, April. 



Description. — Hertwig's (1884) figures and account of this species are the basis of tliis 

 description written from our present knowledge of the structure of the genus, which enables us 

 to interpret his data more completely. The body is rotund, wider posteriorly, its extreme length 

 in life, excluding prod, 1.4 transdiameters. The anterior part is flattened dorsoventrally and 

 expanded laterally, the widest part being slightly posterior to the equator. The dorsoventral 

 diameter is 0.99 of the transverse. The epicone is low and flattened anteriorly, its length is 0.2 

 of the total length. There appears to be a slight anterior horn, an elevation probably encircled 

 by an apical spiral which is evidently the anterior extension of the sulcus upon the epicone. 

 In Hertwig's figures (1884, pi. 6, figs. 3, 5) of this spiral it passes at the right side of the horn 

 and thence around to the left, not the reverse, as in our figures of this region in other species. 

 The hypocone forms at least 0.9 of the body, is almost circular in cross-section in the equatorial 

 region, flattened somewhat ventrally, truncated posteriorly and is cleft to the center by the deep 

 slitlike tentacular recess. 



The girdle is not clearly or consistently figured. It may begin anterior to the ocellus and 

 terminate near the problematical tentacle-like structure figured by Hert'U'ig in the right mid- 

 ventral region. If so, its displacement is about 0.35 transdiameter, and the spiral crown on the 

 anterior margin of Hertwig's figure must be in the rear, not the front of the body, and the 

 central spiral loop on the epicoue of his figure must be the amoeboid upper end of the anterior 

 spiral of the sulcus, and not any part of the girdle or transverse flagellum. There are sug- 

 gestions in the contours of Hertwig's figures of paracingular lines and bands, but they are not 

 defined in either text or figures. The sulcus likewise is not indicated at all in his view of the 

 ventral surface sketched from memory of the living form. The tentacular recess is clearly 

 defined only in the one view (see his fig. 3) from the posterior end. It cleaves the body to the 

 center, but no indication of its antei-ior limits in the body in life or in the preserved individual 

 are available. The prod, as figured and described, is a cylindrical truncated structure twice 

 the length of the body when contracted and four times its length when expanded. Neither 

 granulations on the surface nor terminal stylet were noted, and no axial fiber, although Vogt 

 (18856, fig. 1) reproduces Hertwig's figure with such an axis to demonstrate its similarity to 

 the stalk of a vorticellid. Hertwig (1884) does, however, note the presence of folds on the prod 

 at disintegration, presumably the lines of constriction of the circular fibers. 



The ocellus is located opposite the region of the intereingular part of the sulcus. It is of 

 the simple type with a spherical lens with concentric laminae and a flattened hemispherical, 

 red-pigment mass. Its total length is about 0.35 the total length or 0.45 transdiameter and its 

 axis is deflected to the left and ventrally about 5° from the major axis. The diameter of the 

 lens is a little over 0.25 transdiameter and it is sunk into the pigment mass for about one-third 

 of its diameter. It is made up of five concentric laminae, the outermost of which contains a 

 lens-shaped thickening on its axial, anteriorly directed region. The pigment mass is a reddish, 

 flattened hemisphere, 1.35 times the diameter of the lens in diameter on its posterior face, and 

 a lo\\' truncated cone anteriorly into which the lens fits. In the stained and mounted specimen 

 the pigment mass shows radial striations and cleaves along these lines. No central core was noted. 



The nucleus is an ellipsoidal body, 0.6 transdiameter in length, flattened on the ventral face 

 (by shrinkage?) and located near the center of the body. It has a chromatin reticulum but 

 not moniliform threads. Numerous reddish-brown granules are scattered in the peripheral 

 plasma, especially posteriorly. 



