£i MAZATLAN BEYOZOA 



and belo^v. This form bears considerable resemblance to Mem- 

 braniiJora Sarartii {Sarhjny, Egypt, pi. 10: M. Lacroixii 5. M. 

 Cat. J). 60, pi. lOi, fig. 1.) : but difiers from it in several impor- 

 tant respects ; among wbieb may be noticed tlie narrow brown 

 line surroimding the ceUs and clearly defining one from tbe 

 other ; and the irregxdarly shaped branching denticles with 

 which the margin of the interior calcareous aperture is fur- 

 nished. 



Sah. — Mazatlan ; on the shells of Imperator olivaceus, Imp. 

 imguis and Anomia ; Liverpool Collection. 



Tablet 1 contains a group on Imperator. 



2. Membeanipora gothica, Rylands, ms. (n. s.J 



Areis cellularum elongatis, ovalihus ; margine glahro, tenui; 

 ore elevato, suhorhieulaH, ivferne late sinuato ; cellularum 

 superjieie anferiori calcared dejjressd, ptimctatd, orificio magna 

 utrinque perforata ; aviculariis magnis, immersis, irregulariter 

 per polyzoarium sparsis. 



There is occasionally a short blunt spine or process on each 

 side of the mouth, a character which also exists in M. Eozieri, 

 Savigny, (B. M. Cat. p. 59, pi. 65, fig. 6,) a species to which the 

 present exhibits in other respects considerable resemblance, 

 and especially in the existence of the large opening on each side 

 of the front of the cell immediately below the mouth. The 

 cUfFerences between the two, however, are sufficiently striking. 

 In ]\I. Eozieri the ovicell is large, superior, rounded, and carinate 

 in front ; whilst in M. gothica, as in ]\r. calpensis, Basl\ &c., 

 this organ appears to be represented by one or two rounded 

 eminences at the bottom of the ceU in front. The large scat- 

 tered avicidaria also, are characteristic of the present form, as 

 well as its much larger size. 



The same species occurs on a pearl-oyster shell, for which 

 I am indebted to Dr. J. E. Gray ; the habitat assigned to wliich 

 is doubtfully given as the Persian Gulf. In ]\I. M. Edwards' 

 Memoir Siir Ics JEscharcs, p. 17, pi. 12, fig. 13, amiocene fossil is 

 described and figured, which bears considerable resemblance to 

 the present ; it differs principally, so far as can be determined 

 from the figure alone, in the thickened and granidated margin 

 (.if the area. 



JInh. — JMazatlan : on Imperator olivaceus and unguis ; L'pool 

 Col. 



Tablet 2 contains a group on Imperator. — 3, a group detached. 



