96 f- IHMA. 



with a sieve-plate. Tt almoFit directly conimniiicatns with cffrU'ent 

 canals, haixlly leaving a common gastral cavity. In one of niy spssi- 

 niens, the cones centralis projects considerahly out of th^ gastral 

 opening ; in others I find no trace of a central cone. Of the different 

 spicules, the following niay l)e mentioned as principal distinctive 

 points of the present species : 



Dermal pinuli, shaped as in H. apprtiim, but somewhat shorter, 

 not exceeding 0. 12 mm. in height, while the hasal cross has compara- 

 tively long and slender arms (0.;]5 nmi. from the centre). The subder- 

 mal framework is formed exclusively of pentacts, the tangential rays of 

 which measure 0.15 — 0.'22 mm. in length and combine to form a 

 toleral)ly regular, rectangular network. The parenchymals are mostly 

 mediam-sized hexacts with comparatively few diacts. The so-called 

 microhexacts have slender straight arms, .0.> — .09 nun. long, that are 

 almost smooth but prove to be slightly rough under high magnification. 

 Macramphidiscs present the most characteristic feature. They may 

 attain a length of 0.52 mm., furnished with 6-7 rayed, semi-ovoid 

 umbels 0.14 mm. broad and 0.12 nun. long. Their axial shaft is entirely 

 smooth or is occasionally furnished with a few tubercles. i\[esamphi- 

 discs were not found, but micramphidiscs of ordinary appearance are 

 present in a])undance. Anchors of the root-tuft 4 teethed. 



