Distribution of Saccaniniina sphasrica, etc. 9 



(7) Xow the chinks and fissures between the stones on the 

 inner side of the test are filled in with mortar mass. IMoreover, 

 the Pijloiiitubus is strengthened by outward additions (Anlager- 

 ungen), and has thereby reached its iinal completion. The test 

 is perfect. 



" With this marshalling of the development into seven stages, 

 it must be particularly pointed out that the characteristic features 

 of several and consecutive stages appear at different points of 

 one and the same test, which proves that the whole test does nut 

 proceed simultaneously to a higher stage of structure, but that it 

 is accomplished by degrees. And with this comes the certainty 

 that the above tabulated stages are related to one another, and 

 that they do not represent different species, as people have hitherto 

 believed. It is not at all rare to find tests which, according to 

 the most reliable diagnoses and illustrations, may be taken to be 

 half Psammosjphdsra and half Saccarnriiina" 



The author, in our opinion, takes this correlation too much for 

 granted. 



First, as regards the primordial stage {PrimativgehoAise). If 

 the organism figured and described by Dr. Ehumbler under the term 

 Primativgehduse is really the initial stage of the species, it should 

 occur wherever the adult form is to be found. But the organism 

 figured by Dr. Ehumbler is, so far as an extensive experience of 

 Saccammina gatherings enlightens us, by no means a constant or 

 even a frequent accompaniment of the matured or adult type. 

 We are able to identify Dr. Ehumbler's figures 1-5 {6, plate 21) as 

 a complete life-history of a distinct and well-recognized Ehizopod, 

 Crithionina mamilla of Axel Goes {10), which occurs in company 

 wi.th Saccammina sphserica in many of the ' Goldseeker ' dredgings, 

 and the specimens agree both as regards figure and description 

 with Dr. Ehumbler's Primativgehcmse* (Plate III.) The white 

 colour of the fine interstitial cement to which Dr. Ehumbler draws 

 particular attention, and which colour he regards as a proof of its 

 juvenile status, is a characteristic feature of this species of Crithio- 

 nina in all stages of its development. Now^ Crithionina mamilla is 

 a perfectly well defined and constant type of Ehizopod, belonging to 

 a separate sub-family, and presenting no feature in common with 

 Saccammina, except the possession of an adventitiously constructed 

 test. Crithionina mamilla, which w^as originally described from 

 the same Norwegian localities in which Saccammina abounds, 

 occurs not only in many of the ' Goldseeker ' dredgings throughout 

 the North Sea, but there are other records of its occurrence, notably 

 one by Mr. F. W. Millett in the Malay Archipelago, where Sac- 



* In the " Summary of Families " in Dr. Ehumbler's later " Zusammenstel- 

 lung" [11), he caUs attention (p. 231) to the likeness of his "Youthful forms of 

 Saccammina " to Crithionina, so that he must not be presumed to have overlooked 

 this form. 



