NOTES ON RETICULARIAN RHIZOPODA. 23 



his work on the Microscope, before alluded to, Dr. Carpenter 

 describes and figures many other forms under such names 

 as " Orbuline Lituola," '' Globigerine Lituola," " Orthoce- 

 rine Lituola," and the like. It is much to be regretted that 

 many of these which represent important genera, have 

 never been adequately illustrated, so that they are but 

 little known, except to the few who possess verified speci- 

 mens. Some of them might very properly have been 

 treated in the present paper, for with one or two exceptions 

 they all have been found in the " Challenger" material, but 

 the limited space available for figures is already crowded 

 with forms for the most part even less known than they are. 

 After all, it is only a few out of a large number of new 

 species that can be alluded to in a brief notice of this sort, 

 and the object has been to select salient types, and leave the 

 intermediate forms for the more extended memoir which 

 will be furnished in the official account of the " Challensfer'' 

 cruise. 



The 'Introduction to the Study of the Forarainifera,' 

 by Dr. Carpenter and INIessrs. Parker and Rupert Jones, 

 may be accepted as the epitome of our knowledge of the 

 Order, so far at least as it depends on the minute structure 

 of their tests, at the time of its publication in 1862. In this 

 work the arenaceous types constitute the family Lituolida, 

 and are distributed under three generic heads — Lituola, 

 Trochammina, and Valvtili?ia. Lituola is characterised as 

 having a test rough and sandy on the exterior, the interior 

 of the chambers being either simple and undivided or laby- 

 rinthic. Trochammina is distinguished by the finer mate- 

 rials selected for the construction of the test and the larger 

 proportion of calcareous or ferruginous cement used in their 

 incorporation. The shell-structure in Valvulina is described 

 as more open to variation, usually rough and sandy as to its 

 exterior, but sometimes revealing a perforate, calcareous, 

 shelly basis beneath, and the triserial arrangement of the cham- 

 bers is accepted as the most noteworthy character of the genus. 



Professor Reuss, writing about the same time, whilst ad- 

 mitting the difficulties of the position, proposes to divide the 

 somewhat unwieldy group included in the genus Lituola 

 of English systematists ; and, as a matter of convenience, 

 there was even then, no doubt, much to be said in favour of 

 his view. In his latest work,* published after his death, he 

 divides the family Lituolidea of his classification, which is 

 scarcely coextensive with the genus Lituola of the "Introduc- 

 tion," into four genera — Polyphragma, Haplophragmiuyn, 

 > 'Das Elbthalgeberge in Sachsen,' 2ter Theil, p. 119, 1874. 



