MUELLERIKI.I.A. 



435 



Ascidians, off Hull. They are all fossil or marine, and inhabit especially the 



torrid and arctic regions. 



We give here the 

 frustule (fig. 158^), and the valve (fig. 158,7), 

 of Stcphanopyxis corona (E/ir.), Gntn. 

 (Systephania E/ir.), which is found in the 

 Nottingham deposit. Trochosira mirabilis 

 Kitt., (fig. 159^7), and Trochosira Spinosa 

 Kitt. (fig. 159/;, c), are both found in the " moler " of Mors (Jutland). 



c. 



Fig. T59. a. Trochosira mirabilis 

 h. c. Trochosira spinosa. 



GENUS 104. 



MUELLERIELLA, H.V.H., 1894. 



Valves elliptic, with non-cellu- 

 lar structure, the median portion 

 apparently smooth, with short 

 scattered spines, margins robust, 

 divided into numerous rectangular 

 compartments, formed by the pre- 

 sence of perpendicular costae at the 



margin. 



Fig. 160. Muelleriella limbata. 



We have pleasure in dedicating this 

 new genus to our friend the Baron and 

 Dr. Ferd von Mueller, the learned 

 explorer of Australia, who for more 

 than twenty years has honoured me 



by keeping me au courant with his works. 



M. limbata (Ehr.) H.V.H. {Pyxidicula limbata Ehr., H.V.H. 

 Arl, pi. 8 3 ter, f. 13-14*). 



Valve elliptic, much inflated, convex ; central portion apparently smooth, 

 but really covered with very fine puncta scattered here and there ; other 

 portions irregularly in quincunx ; numerous robust short spines, bifid or trifid, 

 alate, and anastomosing at the bases. Margins very robust, punctate like 

 the median portion, divided into rectangular compartments, in consequence 

 of the presence of internal costae perpendicular to the margins of the valve. 

 Major diameter of the ellipse, 8 to 10 c.d.m. ; minor diameter, about 4 c.d.m. 



Fossil. Sta. Monica (Prep. Weissflog, Nos. 010 and on), Richmond. 



var. Cristagalli Brun. and Temp. (Diat. Japan, p. 40, pi. 8, f. 8). 

 Girdle face broad and like a hood, having the form of a cock's comb. 



Limestone from Sendai and Yedo (Brun). 



