24 



In external appearance specimens 1947 and 1949 of the Siboga material very much 

 resemble the illustration Thiele gives of his Spirastrella insignis. Now those specimens are 

 closely allied to 5. areolata\ all three are devoid of the very large, robust spinispirae. But 

 areolata as well as 1947 and 1949 are also allied to cunctatrix which generally possesses 

 abundantly those robust spinispirae. On the other hand Thiele's specimen in some respects 

 resembles itself cunctatrix. Indeed, taking all into consideration it becomes highly probable that 

 S. insignis is identical with S. cunctatrix. I hope to show by comparison of the whole mass 

 of specimens I examined, that this is not only probable but that it is true. 



XXIX. Spirastrella panis. 



1898 Thiele pp. 43 — 44, 62. PI. II, fig. 3 — 4; PI. VIII, fig. \qa — igd. 



The author mentions three varieties of this "new species" viz. rugosa, massalis and 

 anaineusis. Between the former and S. insignis I cannot see any difference of specific value. 

 Thiele states further (1. c. p. 43) that one of his varieties (which?) "in der Nadelform sich 



Spirastrella cunctatrix nahert, wahrend die Form der von Spirastrella papillosa R. u. D. 



ahnlich ist". Now ciinctatrix and papillosa, as stated before, are so closely allied that I believe 

 them to belong to one and the same species. Many specimens of the Siboga Spirastrellae 

 resemble in external appearance and in spiculation both panis and cunctatrix. The fact is that 

 they are not specifically to be distinguished from each other, nor from cunctatrix, papillosa 

 or panis. 



XXX. Spirastrella tentorioides. 



1905 Dendy p. 125 — 126; PI. V, fig. 7. 

 1909 Hentschel p. 383 — 384. 



The type of Dendy's Spirastrella tentorioides is registered in the British Museum '07. 2. 1 . 124 

 and received my number B. M. l8- 



Dendy writes p. 126: "Considering the extraordinary variation which the species ot 

 Spirastrella exhibit, alike in external form and in the arrangement of pores and vents, I should 

 hardly have considered characters of this nature alone sufficiënt to justify the establishment of 

 a new one, but should have regarded this form as yet another variety of Spirastrella vagabunda. 

 We have here, however, a stout form of the spiraster which is, perhaps, not represented in 

 any of the varieties of that species, and this fact, taken in conjunction with the other characters, 

 seem to me to justify a specific separation". In discussing the specific value of 5". areolata I 

 hint at the little specific value that can be attached to the presence or absence of "stout" 

 spinispirae. We will see hereafter that even in this respect Spirastrella shows all gradual 

 transitions in different specimens. Consequently the value for specific distinction diminishes, 

 and I do not hesitate to accept Dendy's suggestion about the identity of 5. tentorioides and 

 5. vagaóunda a. o. In many respects 5". tentorioides resembles S. inconstans. At least I find in 

 the Siboga specimens some which are undoubtly identical (specifically) inter se, on the other 

 hand strikingly agree partly with 5. inconstans partly with S. tentorioides. 



