PENNIRETIPORA. 185 



Size. — Length of fragment 14 mm., width of central stem 1 mm., length of 

 fenestrules 1 mm. 



Locality. — Lummaton. A defective specimen is in Mr. Champernowne's 

 Collection. 



Remarks. — This specimen, though too imperfect for specific (or perhaps 

 generic) determination, seemed worth recording, as its large size, its stem, and 

 the remains of its ramification point to its being the remnant of some form 

 otherwise unknown in these beds. No structure is observable, the lower or 

 perfect part of the stem being dense. This part has the appearance of having 

 been free, but a closer examination seems to show that lateral branches start from 

 its lower side, though they are hidden by the matrix. 



Dr. Gregory, on examining it, suggested that it might be the " broken-down 

 base of a species of Ptilopora" though remarking that " possibly it might prove 

 something very different, as, for instance, the remains of a Gorgonia." Further 

 examination inclines me more and more to the former supposition. It must, 

 however, be left doubtful until better specimens are found. 



4. Genus. — Penniretipora, d'Orbigny, 1849. * 



Zoarium small, delicate. Lateral branches short, free. Cells in two rows, 

 which are divided by a median keel, which is fainter or wanting on the lateral 

 branches. 



1. Penniretipoea (?), sp. PL XX, figs. 7, 7 a, 8, 8 a, 10, 10 a. 



Description. — Zoarium consisting of a central stem about "5 mm. in width, 

 decreasing very slowly, and giving out alternating branches from each side at an 

 angle of about 60°, which are at first much smaller than the principal stem, but 

 which sometimes (at least) expand, and in turn bear smaller branches. Cells 

 arranged in two alternating ranges (on the main stem). Secondary branches 

 about 1 mm. apart, with several sharp longitudinal ridges on one side. Reverse 

 surface of main stem minutely punctate. 



Size. — A fragmentary specimen measures about 10 mm. 



Locality. — One specimen in the Woodwardian Museum, and three in my 

 Collection, are from Lummaton. 



1 1849, d'Orbigny, ' Prod.,' vol. i, p. 45. 



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