IIQ REPORT- — 1855. 



Dr. Lankester exhibited the model of a dredge, invented by Mr. Dempster. 



Exhibilmi of a Copy of the ^Natural History of Deeside and Braemar,' 

 by the late Dr. Macgilli.vray, and edited by Dr. Lankester. 

 The manuscript of this work had been purchased by the Queen, and was now 

 Dublished bv Her Majesty's command. The work consists of an account ot a per- 

 sona our made by the author in 1853, lists of the plants, animals, and minerals 

 Td a compSe map of the district, with woodcuts illustrative of the scenery in the 

 neighbourhood of Balmoral. 



On the Cultivation of Sea-sand or Sand-hills. 

 By the Rev. Dr. Paterson, of Glasgoiv. 



Dr. Lankester exhibited a series of photographs on glass, of various b|ftological 

 and natural history objects, executed by Dr. Redfern, of Aberdeen They were 

 done according to the suggestions made by Mr. Wenham at the last Meetmg of the 

 Association at Liverpool. 



Mr. Patterson exhibited a series of Zoological Diagrams prepared by him for the 

 Government Department of Science and Art. 



Physiology. 



On the signification of the so-called Ova of the Hippocrepian Polyzoa, and 

 on the Development of the proper Embryo in these Animals. By Pro- 

 fessor Allman, F.R.S. 



The author maintained that the pecuhar egg-like bodies which are found so 

 abundantly in the endocystal cavity of almost all the Hippocrepian Polyzoa, and 

 which had been hitherto universally viewed as ova, are not ova, but gemmm, pecu- 

 liarly encysted, and destined to remain for a period in a quiescent pupa-iike state. 

 The very earliest stages of their development are all that can be followed, as they 

 soon become enveloped in an opake horny investment which entirely conceals all 

 internal structure. From such examination, however, as they admit of, it can be 

 seen that they never present the least trace of germinal vesicle or germinal spot, nor 

 do they undergo segmentation. After a time the horny covering splits into two 

 valves, and allows the young polyzoon to escape, in all essential points resembling 

 the adult, and never presenting the general ciliated surface which is always found in 

 the true embryo. The bodies under consideration are invariably produced in the long 

 chord or funiculus which connects the fundus of the stomach of the polypid with the 

 bottom of the cell, and are plainly developed as buds from its substance. They may 

 be seen in reo-ular stages of growth from the proximate to the remote extremity of the 

 funiculus, betng younger as they recede from the stomach. The funiculus, with its 

 peculiar -^emms,' reminds us of' the gemmiferous stolon in the interior of the soli- 

 tary individuals of Salpa. To the bodies in question, the author proposed to give 

 the name of stafoblasts. They present a striking analogy with the so-called " ephip- 

 pial ova" of Daphiiia, and the " winter ova" of the Rotiferse, which latter have 

 been already brought into the category of gemmse by Huxley (Quarterly Journal 

 of Microscopical Science, October 1852). While the characters of the statoblasts are 

 thus much more in accordance with those of gemmse than of ova, their real nature 

 appears to be entirely set at rest by the fact that there also exists in the Polyzoa a true 

 ovary with genuine ova. The author has made out this organ very distinctly in 

 Alcyonella. It is there developed in the walls of tlie endocyst, near the anterior 

 extremity of the cell. It appears as a slightly pedunculated roundish mass, filled 

 with spherical ova, each presenting a large germinal vesicle and very distinct ger- 

 minal spot. The ovum undergoes segmentation, and soon after the mulberry-like 



