348 W. ARCHER. 



always rudely applied, stratum oi foreign fragmentary objects, 

 such as arenaceous particles and diatomaceous frustules, &c. 

 Such would seem to be Lithocolla (Eilh. Schulze), and possibly 

 Elaeorhanis (GreefF). 



I propose, then, next to take up the newly recorded forms 

 falling under such a group intermediate between the naked and 

 truly Skeletophorous forms, and possessing an outer stratum 

 which must at least be a true secretion-product, yet without 

 spines or spicules. The reasons which induce me to dis- 

 agree in this regard with Hertwig and Lesser and to the 

 proposal of such a group will present themselves on con- 

 sidei'ing the forms as they turn up. 



Heliozoa Chlamydophora. 



I propose to group under this designation necessarily only 

 such E-hizopoda as are of a true homaxial nature, and, like 

 the Askeleta, indeed, without spicules or spines or any solid 

 or hard skeleton, but with a distinct highly diiferentiated 

 soft and more or less mobile external envelope, either granu- 

 lar or of a striate appearance, or seemingly quite homoge- 

 neous in nature. The form named by Eilhard Schulze Hete- 

 rophrys varians — the same thing, I believe, as Greeff's Helio- 

 phrys variabilis — should not, I conceive, be included here, 

 owing to its not being strictly homaxial, but must, I fancy, 

 be ad intei'im relegated to Hertwig and Lesser's incongruous 

 group along with Leptophrys, »&c. 



Astrodisculus, Greeff.i 

 This genus, so far as the forms appertaining to it are 

 approximately known, seems to offer the most marked exemplar 

 of the chlamydophorous askeletous type. As the descriptions, 

 so far as they are given by Greeff, have been already repro- 

 duced in the pages of this Journal (1. c), it would be unneces- 

 sary to repeat them in detail. It is, hoAvever, desirable to point 

 out, as bearing on the question under consideration, that the 

 outer region appears to be of a soft and homogeneous nature, 

 hyaline, and sharply bounded at the periphery. It is true 

 that Greeff regarded this outer zone in his A. minntus as 

 probably siliceous and extremely minutely perforate, to allow 

 the passage outwards of the pseudopodia — if that were truly 

 the case it would be " desmothoracous.^' He makes, indeed, 

 the important observation, if confirmed, that it was not 

 altered by application of sulphuric acid. Still, he goes on to 



^ Greeff, " Ueber Radiolarien-artige E-hizopoden des siissen Wassers," in 

 Schultze's ' Archiv f. Mikr. Anat.,' Bd. v, p. 496, ' Quarterly Journ. Micr. 

 Sci.,' vol. X, p. 113 et seq. 



