referred to the Cirripedia. 115 



EXPLANATION OP ILLUSTEATION ON OPPOSITE PAGE. 



Fig. l.—Protobalanus hamiltonensis, R. P. Whitfield. Middle Devonian, 

 Hamilton Group (Mareellus Shales): Avon, Genessee Co., N.Y. (Copied 

 from figure in Hall & Clarke, Palceont. New York, 1888, pi. xxxvi, fig. 23.) 

 Shell viewed from above, c, carina ; r, rostrum ; I, lateralia. 



Fig. 2. — Paleeocreusia devonica, J. M. Clarke. Middle Devonian, Corniferous 

 Limestone: Avon, Genessee Co., N.Y. (Copied from figure in Hall<& Clarke, 

 torn, cit., pi. xxxvi, fig. 26.) Shell viewed from above,- embedded in 

 Favosites hemisplicericus. 



FlG. 3. — Hercolepas signatus, Aurivillius sp. Upper Silurian, bed e 

 ( = Lower Ludlow) : I. of Gotland. (After Aurivillius.) Side view, 

 c, carina ; s, scutum ; t, tergum ; c.l. carino-latera ; I, lateral ; r, rostrum. 



Fig. 4. — Strobilepas spinigera, J. M. Clarke. Middle Devonian, Hamilton 

 Group, Hamilton Shales : Canandaigua Lake, N.Y. (After J. M. Clarke.) 

 a, ' dorsal view ' ; b, side view. 



Fig. 5. — Lepidocoleus sarlei, J. M. Clarke. Middle Silurian, Niagara Shales: 

 Rochester, N.Y. (After J. M. Clarke.) a, side view ; b, diagrammatic 

 transverse section. 



Fig. 6. — Plumulites peachi, Nicholson & Etheridge, jun. Upper Ordovician, 

 Drummuck Group : Whitehouse Bay, Girvan, Ayrshire. Type-specimen, 

 figured Etheridge, jun. & Nicholson, Mon. Silur. Foss. Girvan, pi. xx, 

 fig. 8. (After F. R. Cowper Reed.) Mr. Cowper Reed figures this as the 

 inner view, but it seems to me to be the outer view. An incomplete 

 individual showing the two median rows of abutting plates (to) and the 

 lateral kite-shaped plates (I). 



Fig. 7. — Ttirrilepas wrightiana, de Koninck sp. Middle Silurian, Wenlock 

 Beds : Dudley, Worcestershire. (After H. Woodward.) a, basal half 

 of an individual, showing the two median rows of intersecting keeled plates 

 (to) and a row of lateral plates (I) • b, diagrammatic transverse section. 



plates have them, or only some; these areas appear to be smooth. 

 No information is available as to the structure of the walls of the 

 shell, which is so characteristic in the members of the Balanidae. 

 From the figure, however, it would seem that the apices of the three 

 pairs of lateralia nearest the carina meet on a line extending from the 

 apex of the carina to that of the rostrum. There do not appear to be 

 any fractures due to flattening during fossilization, although a portion 

 of the shell near the margin of the whole of the right side has been 

 creased by compression. Since, however, the original describer states 

 that the shell is depressed-convex, one gains the impression that the 

 whole of the shell has not been flattened. If, therefore, the two 

 pairs of lateralia adjoining the rostrum extended near to the median 

 line as do the remaining unbroken lateralia, then it is difficult to 

 understand where the opercular valves could have been situated. 

 A re-examination of the specimen would be interesting, but it may 

 now be said that it is exceedingly improbable that it is even remotely 

 related to the genus Balanus, or to any other member of the Balanidae. 



Falaocreusia devonica (Fig. 2) is known .by a single shell in which 

 the separate plates cannot be made out ; it is ovate in outline, patelli- 

 form, with the surface gently conical, and slightly depressed on the 

 posterior slope. The wall of the shell is apparently thin, and the 

 surface marked with faint radiating stria? or elevated lines. A con- 

 spicuous furrow extends near to and concentric with the margin. 

 Length 10 mm., width 8'5 mm. As the author states, it brings to 



