SUPPLEMENT.— POLYPLECTUS. clvii 



No other figured species with which I am acquainted seems to have any resem- 

 blance when proportions and the radial curve are considered, so that the species to 

 be described appears to belong to a particularly scarce series. 



1. Vacekia Stephensi, 8. Buchman. Suppl., Plate X, figs. 17 — 19; Suppl., Fig. 



156, p. clxvii; Fig. 162 in text. 



Description. — Given under the generic definition. The ornament consists of 

 very obscure but somewhat distant costse, which later become definite and more 

 numerous. 



Remarks. — Since this species was first figured another example has been found 

 in a parcel of specimens collected some years ago. As this example is larger and 

 gives important additional features, a figure is inserted in the 

 text. The development of the costre is noteworthy in this 

 example. 



This species has a certain resemblance in general features 

 to Asthenoceras nannodes (see p. xlix) ; and this is remarkable 

 considering that the date of existence is about the same. But, 

 apart from the great difference in the radial curve, this species is 

 much less umbilicate, and has a distinctly tabulate periphery. 



Locality and Stratum. — Dorset: Bradford Abbas, and, 

 iudgine: by the matrix, from the Paving Bed ; Stoke Knap, Fia.iG2.—raceicia stephensi, 



•' ' n J . D l Building Stone, Stoke 



from the Building Stone. Knap, Dorset. 



Date of Existence. — Bradfordensis hemera. The find at Stoke Knap fixes the 

 date as not earlier than that ; the Paving 1 Bed of Bradford Almas is not later. 



SuBFALCIEADIATE. 



Nons&pticarinate. 

 LXIII. Genus — Polyplectus, 8. Bud,' mint. 



1890. Polyplectus, This Monogr., p. 214. 



Remarks. — A genus closely connected with Harjpoceras, and the absence of a 

 septicarina perhaps due to degeneration. The much less falcate radial line 

 ( Pig. 158, p. clxvii.) is a good distinction from that genus. 



1. Polyplectus d i scoides (Zieten). Plate XXXVII, figs. 1— 5; Suppl., Fig. L57, 



1 1. clxvii. 

 1890. Polyplectus discoides, This Monogr., p. 215. 



