852 SUMMARY OF CURRENT RESEARCHES RELATING TO 



appendage and the telescopic tail of his Vorticella telescopica, and the 

 specific title of caudata is bestowed in allusion to this appendage. 



Abyssal Type of Orbitolites.* — Dr. W. B. Carpenter makes his 

 observations on this foramiuifer the basis of a study in the theory of 

 descent. He commences by reminding the reader of his earlier re- 

 searches into the history of the Foramiuifera, where he was able to 

 trace a pedigree from the typical Orbitolites, which shows no trace of 

 spiral growth, to the spiral Orhilucina ; want of material prevented 

 him from carrying the pedigree back with certainty to the milioline 

 type, though he was able to express his belief that Orhitolites was the 

 most specialized of the Miliolida. 



The dredgiugs of the 'Porcupine' in 1869 brought up a new 

 form of Orbitoline disk, which comjiletely realized the hypothetical 

 pedigree. This disk commences as a minute primordial chamber, 

 which first extends itself into a closely coiled spiral tube like that of 

 a Cornusinm, then shows an incipient septation in the later coils of 

 this tube, which constitutes it a Spiroloculina ; then flattens out, and 

 becomes camerated as a Peneroplis ; then undergoes the subdivision of 

 its chambers which converts it into an Orbiculina ; and, finally, by the 

 fusion of the lateral extensions of the chambers into complete annuli, 

 assumes the cyclical plan of growth characteristic of Orhitolites. 



We see then an individual passing through what, in the classifica- 

 tion of D'Orbigny, are regarded as four different orders ; while we are 

 led to recognize that, in the Foramiuifera, plan of growth is a character 

 of secondary value. 



The w^hole of the observations may be thus summed up : — 



1. There has been a progressive specialization in the structure of 

 the shelly envelope, which in the highest forms becomes of extra- 

 ordinary complexity. 



2. This specialization has followed a very definite and well-marked 

 line. 



3. It is without any corresponding specialization in the structure 

 of the animal, whose protoplasm retains throughout its primitive 

 homogeneousness. 



4. All the ancestral forms through which the highest type has 

 passed are still living and flourishing under exactly the same con- 

 ditions (so far as can be ascertained) as itself. 



After a careful consideration, the author comes to the conclusion 

 that here a " plan " in the variations may be clearly traced out, and 

 that " natural selection " can have had scarcely any share in deter- 

 mining the progressive evolution and relative distribution of the 

 several forms of the Orbitoline type. 



Trypanosoma balbiani.f — A. Certes refers to an article by Mitro- 

 phanow, in a recent number of the ' Biologisches Centralblatt,' on the 

 haematozoa of fishes, where the two new species of Hcematomonas are 

 described ; the only difference between these and Trypanosoma balbiani 

 appears to lie in their possession of a long flagellum. In an earlier 



* Proc. Roy. Soc, xxxv. (1883) pp. 276-9. 



t Bull. Soc. Zool. Fruuce, viii. (1S83) pp. 209-10. 



