PYCINASTER SENONENSIS. 1»5 



GcHHs— PYCINASTER,' nom. nov. 



Pycnaster, Shxden, 1891 (see p. 21), uou Pomel, 1883. Classif. me'thoJ. Ecliiu., p. 42. 



1. Pycinastkr angustatus, Shulen sp. (see p. 21). PI. IX, figs. 1 '/, 1 1> ; PI. XXI, 



figs. 2, 2a ; PI. XXV, fig. 7 ; 

 PI. XXVI, figs. 4, 4 a, 4 b. 



This species appears to be quite common in the Upper ('lialk. An exceedingly 

 well-preserved specimen is in the collection of Dr. Blackmore, of Salisbury. 



The following specimens, which belong to the genus Piiriwistev, and probably to 

 tliis species, have been erroneously ascribed by me to other genera and si)ecies in 

 Part III of this volume (pp. 67-90). 



The single specimen described on p. 73 as a new species, Pentagonastev rohustns, 

 is probably an innnature form of this species. A collection of five ossicles described 

 (p. 89) as Pcntaceros, sp., and the specimen figured on I'l. XXVI as Calliderma 

 mosaicnm, also belong to the species. The latter specimen should be described as 

 from the Upper f'halk. 



Dom Aurelien Valette has courteously enabled nie to examine the syn-types of 

 his Arthmxtpr senonensis (' Bull. Soc. Sci. Yonne,' 1902, p. 20). They prove to be 

 marginals of Pijrin<i^f<-r (ingustatus. Four ossicles referred by him to \\\?,Pentaceros 

 senonensis (vide infra) also belong to the present species. 



2. PVCIXASTER SENOXEX.SIS, Wdcttc, sp. PI. XXVI, fig.s. 1, \(i, ll>; PI. XXIX, 



figs. 6, 6 (J. 



Pentaceros senonensis, Valette, 1902. Bull. Soc. Sci. Yonue, vol. hi, pp. 17, 18, 



figs. 1, 2 (uou 3—7). 

 — puNCTATUs, Spencer, 1905. Anfea, p. 88. 



Dr. Biackmore's material enables me delinitely to ascribe this species to 

 Pyciiiastcr, and to add the following new diagnosis and details : 



Specific Chardcti'rs. — Body of large size. Breadth of marginaUa more than 

 twice their thickness. All marginalia smooth or with very shallow hexagonal 

 spine-pits. 



Description. — The marginaUa may l)e as much as 20 mm. high. They api)ear 



to be distinguished from the marginalia of P. anijnHtahts, not only by their 



1 lIvKifiit, compact, Homeric form of iri//ciiii. Dom Auri'lien Valette kiudly poiuted out the 

 prior use of Pyciiaster to Dr. F. A. liathcr, who suggests the above emeudatiou. 



