342 Messrs. W. K. Parker and T. R. Jones on the 



of British Forarninifera. Not only were several new forms added 

 to the list, but improved figures and more elaborate descriptions 

 were substituted for the imperfect ones hitherto published. In 

 the first of these publications the difficulty of defining the limits 

 of specific variation obviously dawned upon the mind of the 

 author; and in describing his Vermiculum intortum (Miliolina 

 Seminulum) he distinctly states that this is so variable in its 

 formation, that, without great attention, it might be formed 

 into several species, — a warning that might have been received 

 with advantage by many of Montagu's successors in the study 

 of Foraminifera. Shortly after the appearance of Montagu's 

 first volume, the publication of the 'Testacea Microscopica ' of 

 Fichtel and Moll indicated that these accurate observers had 

 obtained further light respecting the variableness of many of the 

 Foraminifera, — a fact especially demonstrated by their descrip- 

 tion of Nautilus Calcar (Crist ellaria Calcar) ; but notwithstand- 

 ng his previous experience, when publishing his f Supplement/ 

 Montagu was unable to follow these authors in their accurate 

 determinations. ' If,' he remarks, speaking of the numerous 

 forms of N. Calcar delineated by these writers, c these can be 

 admitted as the same species, we may bid defiance to specific 

 definition.' Nevertheless Fichtel and Moll were in all proba- 

 bility right." 



The ' Test. Brit.' (which consists of two parts continuously 

 paged — Part I., with Introduction and pp. 1-292, and Part II. 

 pp. 293-606) contains thirty short descriptions of specimens 

 that, with few exceptions, were in "the Boysian Collection/' 

 and more than half of which had been already described and 

 figured by Walker. Montagu gave figures of six previously 

 undescribed forms, but does not appear to have personally ex- 

 amined all the Boysian specimens, having in some instances 

 worked from drawings and notes received from Mr. Boys. In 

 the l Supplement,' five years afterwards, he described more fully 

 eleven forms, refiguriug most of them; and introduced, with 

 figures of all but one, six that he had not previously noticed. 

 By this time Montagu had had the opportunity of personally 

 examining " the Boysian Collection," presented to him by Mr. 

 Henry Boys, and which seems to have been increased by addi- 

 tions made from the coast-sands since Walker first had it in 

 hand. This examination led Montagu to correct and improve 

 some of his previous descriptions*; but at the same time, from 

 some cause or other, he was evidently led into mistakes as to 

 the identity of specimens already figured by Walker. Thus 



* He had also been enabled to enlarge his knowledge of these minute 

 shells by comparing his recent specimens with fossil Foraminifera brought 

 from Italy by Messrs. Mead and Higginson. 



