176 



SCIENCE. 



[N. S. Vol. VIII. No. 189. 



but as a production of the age of Galileo, 

 Harvey, Gilbert and Keppler, it does not 

 appear as a marvelous performance. The 

 only circumstance at which one hesitates 

 is that a scientific chemist, whose mind 

 moved in the world of reality and veracity, 

 should have mixed the description of his 

 experiments with so much degraded bom- 

 bast. We can only surmise that the 

 wealthy Tholde, or the master spirit behind 

 him, purchased these secrets of antimony 

 from some indigent chemist and worked 

 them into the otherwise nonsensical book 

 in which they appear. 



C. S. PlEECE. 



STUDIES FROM THE ZOOLOGICAL LABORA- 

 TORY, HARVARD UNIVERSITY. 

 The following abstracts of papers pre- 

 pared in the Zoological Laboratory of the 

 Museum of Comparative Zoology at Har- 

 vard College have been made by the authors. 

 The final papers will be published as soon 

 as the plates necessary for their illustration 

 can be prepared. Other papers, not readily 

 given in abstract, or requiring illustrations 

 to make them intelligible in that form, will 

 be published soon. 



E. L. Mark. 



Ovogenesis in Distaplia occidentalis Bitter 

 (MS.), with Bemarks on other Forms. (Ab- 

 stract.) By F. W. Banceoft. 

 The material was all obtained on the 

 coast of California. In the compound as- 

 cidian Distaplia, only, was it attempted to 

 make the investigation at all complete. 

 Here the development of the sexual organs, 

 though in several respects simpler, con- 

 forms to the type described by Van Bene- 

 den et Julin in 1885. Both ovary and 

 testis are derived from a common funda- 

 ment, which, on account of the differentiated 

 oogonia it contains, is recognizable in even 

 the smallest buds of the older colonies. 



One of the diagnostic characters of the 

 genus Distaplia is the capacious brood 



pouch in which the embryos are kept. It 

 is attached to the zooid by a narrow stalk 

 and has usually been described as a diver- 

 ticulum of the peribranchial sac. The em- 

 bryos are arranged so that the youngest are 

 at the tip of the organ. It was found to be 

 not a simple diverticulum ; the stalk of the 

 pouch is double, consisting of two narrow 

 tubes, one of which is a continuation of the 

 oviduct, while the other opens into the 

 peribranchial sac. The oviducal tube 

 opens into the bottom of the pouch, and it 

 is on account of this arrangement that the 

 younger embryos are always found in the 

 tip of the organ. In passing from the 

 ovary to the pouch the ovum is greatly 

 compressed, assuming the shape of a sau- 

 sage, but becomes oval as soon as it has en- 

 tered the pouch. 



The test cells are seen to be derived from 

 the follicular epithelium, and not, as 

 Davidoff has maintained for this genus, 

 from within the ovum. The cytoplasm of 

 the test cells has been stained from the ear- 

 liest stages on, and strands of cytoplasm are 

 seen during all the earlier stages connecting 

 the test cell with the follicle in somewhat 

 the same way that Morgan has described* 

 However, at this period, bends in the wall 

 of the germinative vesicle and accompany- 

 ing vacuoles in the cytoplasm are occasion- 

 ally encountered, and it is likely that these 

 appearances are what has been described 

 by Davidoff as nuclear evaginations from 

 which the test cells are formed. They are 

 probably due to shrinkage. There are also 

 deeply staining granules in the cytoplasm, 

 which often have vacuoles around them, 

 and then look exactly like Davidoff's fig- 

 ures of nuclear buds that have already be- 

 come detached from the germinative vesicle. 

 But they do not produce the test cells, as 

 this author thinks. The test cells are 

 found to take no part in the formation of 

 the test of the embryo, as has recently been 

 maintained by Salensky. The outermost 



