Manchester Memoirs, Vol. Ixii. (19 17) 37' 



Sub-genus Siphogenerina, Schlumberger. 



This sub-genus was founded by Schlumberger in 1883 for 

 the reception of certain species which resemble Bigenerina in 

 the arrangement of their chambers but which are furnished 

 internally with a series of longitudinal median tubes, the tubes 

 only existing in the uniserial portion of the test, and serving 

 to connect the oral orifice of a chamber with the one immediately 

 below it. Schlumberger describes the oral aperture as being, 

 "Excentric, round, bordered by a slight raised rim, and open- 

 ing alternately to the right and left of the axis.'"' That descrip- 

 tion is too narrow to include the many varieties of aperture 

 found in the. sub-genus. I have noted myself 1 — A produced 

 phialine neck which is common in the Lagenidse; 2 — A large 

 circular orifice surrounded by a raised rim; 3 — A large oval 

 orifice surrounded by a raised rim; 4 — A narrow curved slit 

 with a depressed margin, sometimes supplemented by scattered 

 pores on the septal face of the segments. As regards the oral 

 apertures of the biserial portion of the test, they are 

 textularian or bolivine. 



The first published drawing of a bigenerine shell with an 

 internal tube is one given by Goes in "Reticularian Rhizopoda 

 of the Caribbean Sea" (Stockholm, 1882). A figure given in 

 this work (Plate V, fig. 166) plainly shows the internal tube, 

 but Goes does not seem to have realized its significance or 

 perhaps misinterpreted the microscopical image, as he refers 

 later in "The Foraminifera of the U.S.S. Albatross" (1896) to 

 the outlines of the tube as being "a couple of longitudinal folds 

 on each segment." This form is given in the last mentioned 

 memoir a new specific name, viz.: — Sagrina pygmcea. Goes 

 however says that "It is with some hesitation" that he thus 

 distinguishes it. 



The following is a list of species which have an internal 

 tube, and which are generally bigenerine in growth, though 

 occasionally specimens are found which, are not biserial at the 

 commencement. 



1. — 5. raphanus Parker and Jones. 



2 



3 



4 



5 

 6 



7 



8 



9 



10 

 11 



— S. columellaris Brady. 



— 5. dimorpha Parker & Jones. 



— S. striata (Schwager). 



— 6\ calcarata Berthelin. 



— S. pygmcea Goes. 



5". schlumbergerii Millett. 



S. ocracea Schlumberger. 

 — 5. sulcata, sp. n. 

 — S. papulosa, sp. n. 

 — S. hexagona, sp. n. 



