ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 419 



separation of the two parts along the line of fusion. The red blood- 

 corpuscles of the adult Phoronis make their appearance in the young 

 Actinotrocha ; and when the latter become fully developed, they are 

 usually present as one or two pairs (according to the species) of con- 

 spicuous red masses in the larval collar-cavity. But this only indicates 

 the general tenor of the author's observations. 



Lohmanella catenata.* — E. Neresheimer describes this mesozoon 

 parasite from the body of species of Fritillaria. The two-layered young 

 form possesses a marked resemblance to a gastrula. But here the cell- 

 complex which would correspond to the inner layer shows nothing com- 

 parable to a true endoderm, since almost the whole material is used up 

 for the formation of (probably asexual) reproductive bodies, whilst the 

 material corresponding to the ectoderm takes on the function of diges- 

 tion. He believes that this formation arises, not by invagination, but by 

 overgrowth. From a study of stages in the life-history of Ammbophrya, 

 which are analogous to those seen in Lohmanella, the author proposes to 

 group these genera together under the name Blastuiloidea, placing this 

 division in the same rank as those of the Planuloidea and Mesenchymia. 



Rotatoria. 



Rotatoria and Gastrotricha of Ploen.j — In this work of 178 pages 

 Max Voigt gives the results of his investigation of these animals, 

 which he has prosecuted for about twenty months in the lake region of 

 Ploen in Holstein. Altogether 217 species of Rotifers were observed, 

 of which the following four are new species : Cordylosoma perlucidum, 

 Codopus uncinatus, C/i'lopus rousseleti, Distyla ploenensis ; and one, 

 Anurma aculeata var. cochlmris, a new variety, though all these have 

 already been mentioned by the author in a short descriptive account, 

 without figures, in the Zool. Anzeiger in 1902. The most interesting 

 new species is undoubtedly Cordylosoma perluciduni, for which a new 

 genus had to be created, intermediate between the Floscules and the 

 Philodinasa, with a strange combination of characters. 



The author gives an exhaustive account of the occurrence of the 

 various species in the different large and small lakes and pools of the 

 region, as well as of the appearance of the males and the production 

 of resting eggs. 



In a second division an account of "twenty-three Gastrotricha found 

 in the region is given, of which ten are described as new. 



A third division enumerates five parasites found in the body-cavity 

 of various Rotifers. Seven plates, with thirty-nine figures of Rotifers 

 and seventeen figures of Gastrotricha, accompany this memoir. 



A Monograph of the Rattulidae.} — H. S. Jennings has ren- 

 dered a great service to all students of the Rotifera in producing this 

 excellent monograph, which is a thorough revision up to date of the 

 Rotatorian family Rattulidas. The author has very carefully sifted the 



* Zeitschr. wiss. Zool., Ixxvi. (1904) pp. 136-63 (2 pis.). 



t Stuttgart (1904) 178 pp. and 7 pis. Will appear abo In vol. xi. of Forech. Ber. 

 biol. Stat. P16n. 



X Bull. U.S. Fish Com. for 1902, pp. 273-352 (15 pis.). 



2 G 2 



