28 G. C. Crich — Pericydmfasckulatns, M^ Coy. 



genus Pericychis,^ Dr. Foord has shown (op. cit., pt. iv, 1901, pp. 137, 

 138) that the specimens described as P. furcatus are only examples 

 of P. fasciculatiis that have lost the test ; he has therefore united the 

 two species, adopting M'Coy's name fasciculatiis for two reasons, 

 ^' (i) because it was the first to be described in the ' Synopsis,' and 

 (2) because it shows the ornaments on the test, whereas the name 

 furcatus was applied merely to the cast of the shell." 



The following is Dr. Foord's emended description of the species : — 



" Shell discoidal, somewhat inflated, umbilicated ; greatest thick- 

 ness at the umbilical margin, where it is two-thirds of the diameter 

 of the shell ; height of outer whorl two-fifths of the diameter of the 

 shell. Whorls not fewer than five (exact number not ascertainable) ; 

 inclusion about one-half ; umbilicus somewhat less than one-half of 

 the diameter in width, with subangular margin, deep, partly ex- 

 posing the inner whorls. Whorl reniform in section, about twice as 

 wide as high, not much indented by the preceding whorl ; periphery 

 broadly convex, continuous with the convex sides ; inner margin 

 rather wide, well defined, very steep. 



" Body-chamber occupying at least one whorl ; aperture not seen. 

 ■Chambers of modei'ate depth; suture-line as in pi. xxxvii, fig. 6. 

 Test ornamented with strong, rounded, ti'ansverse ribs, which 

 generally begin to bifurcate at or near the umbilical margin, the 

 bifurcation in some specimens not taking place till the middle of the 

 side is reached. The ribs form a broad, shallow sinus in crossing 

 the perijihery, the sinus sometimes becoming sharply concave in the 

 median line ; the intervening concave spaces wider than the ribs. 

 Covering the ribbing and interspaces there are a series of very 

 •distinct, sharp, raised lines, disposed iri-egularly as regards their 

 distance apart ; on the ribs about two of the lines occupy the space 

 of 1 mm., but between them the lines are a little more spread out. 

 The tendency of these fine ribs to form bundles is well marked, and 

 made the name ' fasciculatns ' given by M'Coy to the specimen 

 bearing the test singularly appropriate." 



The reference to the suture-lines is rather misleading, because the 

 figure which Dr. Foord gives is taken from an immature specimen, 

 and shows neither the characteristic pointed lateral lobe nor the 

 existence of a second smaller pointed lobe on the inner area of the 

 whorl. These suture-lines are stated to be those " of a small 

 specimen where the diameter of the shell is about 30 mm.," but it 

 correctly drawn they appear to have been taken from the young 

 stage of a rather large individual, because the lateral lobe is still 

 rounded, whereas in some of the specimens described below this lobe 

 is distinctly pointed at a diameter of less than 30 mm. (See 

 Figs. 2, 3, and 4.) The suture-line of the original of Dr. Foord's 

 pi. xxxvii, figs. 2a, b, which is in the National Collection 

 [No. C. 5933], is therefore given in the accompanying drawing 

 (Fig. 1). In the figure in the "Catalogue of Fossil Cephalopoda, 

 British Museum," pt. iii. p. 150, fig. 71c, the lobe on the inner 

 margin of the whorl should have been represented a little deeper and 

 more acute. 



' See Cat. Foss. Cepli. British Museum, pt. iii (1897), p. 149. 



